Encoder, measurement method and system based on magnetoresistance principle

Abstract

The present invention relates to the technical field of encoder measurement, and discloses an encoder, a measurement method and a system based on the magnetoresistive principle. The encoder includes: a magnetic plate fixed on the motor mover, on which a permanent magnet is provided; a magnetoresistive sensor fixed on the motor stator, with a spacing the same as the pole pitch between the N pole and the S pole of the permanent magnet, and the magnetoresistive sensor is placed in the magnetic field of the magnetic plate; the output signal of the magnetoresistive sensor is connected to an operational amplifier circuit and then to a processor. The method includes: the magnetoresistive sensor converts the magnetic field change into sine and cosine signals, and the sine and cosine signals are converted into digital quantities through an analog-to-digital converter after conditioning and amplification; the processor determines the sector position where the magnetic plate is located in combination with the sine and cosine signals and the signs of the digital quantities, and obtains the position information in combination with the spacing of the magnetoresistive sensor. The system includes an encoder, a data acquisition module, a signal conditioning and conversion module, and a position information calculation module. The present invention can ensure strong anti-interference ability and high precision, and at the same time simplify the assembly process and reduce costs.

Description

Technical Field

[0001] The present invention relates to the technical field of encoder measurement, and in particular to an encoder, a measurement method and a system based on the magnetoresistive principle. 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 several thousand 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 automated equipment that requires high-precision measurement, such as printing, packaging, medical, machine tools, textiles, robots, etc. Encoders usually work together 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, incremental encoders do not provide absolute position information. After the device is powered on, the device needs to perform a homing operation once, and then run according to the incremental position information. Therefore, incremental encoders are easily affected by external interference, resulting in incorrect position accumulation calculations. Absolute encoders are encoded by mechanical positions, without the need for memory or reference point finding. Therefore, absolute encoders have stronger anti-interference ability and higher accuracy compared to incremental encoders. However, absolute encoders also have the disadvantages of complex assembly processes and high costs. Summary of the Invention

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

[0005] To solve the above technical problems, the present invention provides an encoder based on the magnetoresistive principle, including:

[0006] A magnetic plate fixed on the motor mover, on which permanent magnets are evenly distributed;

[0007] A plurality of magnetoresistive sensors fixed on the motor stator, the spacing of the magnetoresistive sensors being the same as the pole pitch between the N poles and S poles of the permanent magnets, and the magnetoresistive sensors being placed in the magnetic field of the magnetic plate;

[0008] An operational amplifier circuit, to which the sine signal and cosine signal output by the magnetoresistive sensors are connected;

[0009] A processor, the sine signal and cosine signal that have passed through the operational amplifier circuit are input into the processor.

[0010] Further, it further 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. The operational amplifier circuit and the bias circuit are arranged on the connection circuit between the processor and the magnetoresistive sensor.

[0011] The present invention also provides an encoder measurement method based on the magnetoresistive principle. When using the encoder based on the magnetoresistive principle, the measurement process of the position information includes:

[0012] The magnetic field of the magnetic plate moves along with the movement of the motor mover. The magnetoresistive sensor converts the magnetic field change into a sine signal and a cosine signal, and after conditioning and amplifying the sine signal and the cosine signal, they are respectively converted into digital quantities; the processor combines the sine signal, the cosine signal, and the signs of the digital quantities to determine the sector position where the magnetic plate is located, and obtains the position information according to the corresponding relationship between the sector position where the magnetic plate is located and the spacing of the magnetoresistive sensor.

[0013] Further, 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:

[0014] V sensor = k1 * Vi,

[0015] wherein, V sensor is the amplitude of the sine signal and the cosine signal, Vi is the supply voltage of the magnetoresistive chip of the magnetoresistive sensor, and k1 is the coefficient of the output signal amplitude of the magnetoresistive chip.

[0016] Further, converting the sine signal and the cosine signal into digital quantities respectively after conditioning and amplifying includes:

[0017] Performing voltage amplification and bias processing on the sine signal and the cosine signal. The sine signal and the cosine signal after voltage amplification and bias processing are:

[0018] V output =k2* V sensor + V ref ,

[0019] wherein, V output is the sine signal and the cosine signal after voltage amplification and bias processing, V sensor is the amplitude of the sine signal and the cosine signal, k2 is the amplification factor, and V ref is the reference bias voltage;

[0020] The sine signal and cosine signal after voltage amplification and bias processing are respectively converted into digital quantities by an analog-to-digital converter.

[0021] Further, combining the sine signal, cosine signal, and the sign of the digital quantity to determine the sector position where the magnetic plate is located, including:

[0022] Calculating the tangent signal of the electrical angle according to the sine signal and cosine signal, and the calculation method of the tangent signal of the electrical angle is: tangent signal = absolute value of sine signal / absolute value of cosine signal;

[0023] Fitting the tangent signal of the electrical angle to obtain the electrical angle value, and the value range of the electrical angle value is 0° to 90°;

[0024] Combining the sign of the digital quantity to extend the electrical angle value to 0° to 360°, and the extended electrical angle value is the angle corresponding to the sector position where the magnetic plate is located.

[0025] Further, when fitting the tangent signal of the electrical angle, the method used is polynomial fitting, specifically:

[0026] θ’ = a * (tanθ) 3 + b * (tanθ) 2 + c * (tanθ) + d,

[0027] where 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.

[0028] Further, combining the sign of the digital quantity to extend the electrical angle value to 0° to 360°, specifically:

[0029] 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 extended electrical angle value is the current electrical angle value falling in the first quadrant;

[0030] 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 extended electrical angle value is the current electrical angle value falling in the second quadrant;

[0031] 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 extended electrical angle value is the current electrical angle value falling in the third quadrant;

[0032] 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 extended electrical angle value is the current electrical angle value falling in the fourth quadrant.

[0033] Further, the position information is obtained according to the correspondence between the sector position where the magnetic plate is located and the spacing of the magnetoresistive sensors, specifically as follows:

[0034] S = D / 360 * θ'',

[0035] where S is the position information finally measured by the encoder based on the magnetoresistive principle, D is the spacing of the magnetoresistive sensors, and θ'' is the angle corresponding to the sector position where the magnetic plate is located.

[0036] The present invention also provides a measurement system for an encoder based on the magnetoresistive principle, including:

[0037] the encoder based on the magnetoresistive principle, a data acquisition module, a signal conditioning and conversion module, and a position information calculation module,

[0038] The data acquisition module is configured to receive the sine signal and cosine signal output by the magnetoresistive sensors, and transmit the sine signal and cosine signal to the signal conditioning and conversion module and the position information calculation module;

[0039] The signal conditioning and conversion module is configured to respectively 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;

[0040] The position information calculation module is configured to control the processor to determine the sector position where the magnetic plate is located in combination with the signs of the sine signal, cosine signal, and digital quantity, and obtain the position information according to the correspondence between the sector position where the magnetic plate is located and the spacing of the magnetoresistive sensors.

[0041] The above technical solution of the present invention has the following beneficial effects compared with the prior art:

[0042] The present invention senses the position change of the mover through the magnetoresistive sensors, and on this basis, calculates the position information through the measurement results of the magnetoresistive sensors. 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. Description of the Drawings

[0043] In order to make the content of the present invention easier to be clearly understood, the following further details the present invention according to the specific embodiments of the present invention in combination with the drawings, where:

[0044] Figure 1 is a schematic structural diagram of an encoder based on the magnetoresistive principle in a preferred embodiment of the present invention.

[0045] Figure 2 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.

[0046] Figure 3 It is the output signal diagram of the magnetoresistive sensor in the encoder based on the magnetoresistive principle in the preferred embodiment of the present invention.

[0047] Figure 4 It is the circuit diagram of the operational amplifier circuit and the bias circuit in the encoder based on the magnetoresistive principle in the preferred embodiment of the present invention.

[0048] Figure 5 It is the flow chart of the measurement method of the encoder based on the magnetoresistive principle in the preferred embodiment of the present invention.

[0049] Explanation of the reference numerals in the specification drawings: 1. Rotor; 2. Magnetic plate; 3. Stator; 4. Sensor circuit board. Detailed implementation manners

[0050] The present invention will be 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 be able to implement it, but the specific embodiments cited are not intended to limit the present invention. Embodiment 1

[0051] Referring to Figure 1 As shown, the present invention discloses an encoder based on the magnetoresistive principle, including a magnetic plate 2, a plurality of magnetoresistive sensors, an operational amplifier circuit and a processor. The magnetic plate 2 is fixed on the motor rotor 1, and permanent magnets are evenly arranged thereon. The magnetic plate 2 moves together with the motor rotor 1 to provide a magnetic field for the magnetoresistive sensors. A plurality of magnetoresistive sensors are fixed on the motor stator 3. In this embodiment, the magnetoresistive sensors are fixed on the side of the motor stator 3. The distance between the magnetoresistive sensors is the same as the pole pitch between the N pole and the S pole of the permanent magnet. The magnetoresistive sensors are placed in the magnetic field of the magnetic plate 2. In this embodiment, the distance between the magnetoresistive sensors and the pole pitch between the N pole and the S pole of the permanent magnet are both 12.5 mm. The sine signal and the cosine signal output by the magnetoresistive sensors are connected to the operational amplifier circuit, and the sine signal and the cosine signal passing through the operational amplifier circuit are connected to the processor.

[0052] 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 as shown in 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 sensors are fixed on the sensor circuit board 4. The magnetoresistive sensors are fixed on the motor stator 3 through the sensor circuit board 4. The number of the sensor circuit boards 4 is determined according to the actual situation. A plurality of magnetoresistive sensors can be arranged on one sensor circuit board 4 or on a plurality of sensor circuit boards 4, as long as the distance between the magnetoresistive sensors is the same as the pole pitch between the N pole and the S pole of the permanent magnet. As shown in Figure 1 、 Figure 2As shown in the figure, in this embodiment, taking the case where multiple sensors are arranged on multiple sensor circuit boards 4 as an example, magnetoresistive sensors are soldered on the sensor circuit boards 4, and the multiple sensor circuit boards 4 are spliced together and fixed on the motor mover 1. An operational amplifier circuit and a bias circuit are arranged on the connection circuit between the processor and the magnetoresistive sensor, and are used for amplifying and biasing the output signal of the magnetoresistive sensor. Embodiment 2

[0053] As Figure 5 shown, the present invention also discloses an encoder measurement method based on the magnetoresistive principle. When using the encoder based on the magnetoresistive principle in Embodiment 1, the measurement process of the position information includes the following steps:

[0054] S1: The magnetic field of the magnetic plate 2 moves with the movement of the motor mover 1, and the magnetoresistive sensor converts the magnetic field change into a sine signal and a cosine signal. When the encoder works, the magnetoresistive sensor senses the magnetic field change and outputs a continuous example diagram in the form of a sine signal and a cosine signal as shown in Figure 3 the figure, where the X-axis output in Figure 3 is the cosine signal and the Y-axis output is the sine signal.

[0055] 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:

[0056] V sensor = k1 * Vi,

[0057] where, V sensor is the amplitude of the sine signal and the cosine signal, Vi is the 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%, and V sensor = ±0.75% * 2.5V = ±18.75mV.

[0058] S2: Convert the sine signal and the cosine signal into digital quantities respectively after conditioning and amplification.

[0059] S2-1: The amplitudes of the sine signal and the cosine signal output by the magnetoresistive sensor are small, so the sine signal and the cosine signal are first subjected to voltage amplification and bias processing. As shown in Figure 4 the figure is the circuit diagram of the operational amplifier circuit and the bias circuit, where U4 is the operational amplifier, and ADC2_IN5 and ADC1_IN9 are the inputs of the analog-to-digital converter. The input signals of this circuit, that is, the signal outputs of the magnetoresistive sensor, are X1-, X1+, Y1-, and Y1+, where X1- is the negative cosine signal, X1+ is the positive cosine signal, Y1- is the negative sine signal, and Y1+ is the positive sine signal; the output of this circuit is the digital quantity processed by the analog-to-digital converter.

[0060] The sine and cosine signals after voltage amplification and bias processing are as follows:

[0061] V output = k2 * V sensor + V ref ,

[0062] where V output is the sine and cosine signals after voltage amplification and bias processing, V sensor is the amplitude of the sine and cosine signals, and k2 is the amplification factor; in this embodiment, Figure 4 in R4 = R10, R1 = R16, the amplification factor k2 = R1 / R4 = R16 / R10 = 56, V ref = 1.25V, V output = ±0.75% * 2.5V * 56 + 1.25V = 0.2V ~ 2.3V.

[0063] S2-2: The sine and cosine signals after voltage amplification and bias processing are respectively converted into digital quantities by an analog-to-digital converter.

[0064] S3: Determine the sector position where the magnetic plate 2 is located by combining the sine signal, cosine signal, and the sign of the digital quantity.

[0065] S3-1: The position calculation of the sensor is based on the arctangent algorithm. First, calculate the tangent signal of the electrical angle according to the sine and cosine signals. 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:

[0066] tanθ = |sinθ| / |cosθ|,

[0067] where tanθ is the tangent signal of the electrical angle, sinθ is the sine signal, and cosθ is the cosine signal.

[0068] S3-2: Fit the tangent signal of the electrical angle to obtain the electrical angle value, and the value range of the electrical angle value is 0° to 90°.

[0069] When fitting the tangent signal of the electrical angle, the method used is polynomial fitting, specifically:

[0070] θ’ = a * (tanθ) 3 + b * (tanθ) 2 + c * (tanθ) + d,

[0071] Among them, 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.

[0072] S3-3: Expand the electrical angle value to 0° to 360° in combination with 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.

[0073] The method of expanding the electrical angle value to 0° to 360° in combination with the sign of the digital quantity is shown in Table 1.

[0074]

[0075] Table 1 Expansion method table of electrical angle value

[0076] As shown in Table 1, the method of expanding the electrical angle value is specifically as follows:

[0077] 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 falling within the first quadrant;

[0078] 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 falling within the second quadrant;

[0079] 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 falling within the third quadrant;

[0080] 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 falling within the fourth quadrant.

[0081] For example, assuming that the electrical angle value obtained by fitting 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, 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, 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, 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, the expanded electrical angle value is 315°.

[0082] S4: Obtain the position information according to the corresponding relationship between the sector position where the magnetic plate 2 is located and the spacing of the magnetoresistive sensor. The calculation method of the position information is:

[0083] S = D / 360 * θ'',

[0084] Wherein, S is the position information finally measured by the encoder based on the magnetoresistive principle, D is the spacing of the magnetoresistive sensor, i.e., 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 where the magnetic plate 2 is located, i.e., the expanded electrical angle value.

[0085] When the encoder measures the position information, the controller and the encoder use the serial port for periodic communication, so that real-time position information can be obtained. Embodiment III

[0086] The present invention also discloses an encoder measurement system based on the magnetoresistive principle, including the encoder based on the magnetoresistive principle in Embodiment I, a data acquisition module, a signal conditioning and conversion module, and a position information calculation module.

[0087] The data acquisition module is used to receive the sine signal and the cosine signal output by the magnetoresistive sensor, and transmit the sine signal and the cosine signal to the signal conditioning and conversion module and the position information calculation module; the signal conditioning and conversion module is used to respectively 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 where the magnetic plate 2 is located in combination with the sine signal, the cosine signal, and the signs of the digital quantities, and obtain the position information according to the corresponding relationship between the sector position where the magnetic plate 2 is located and the spacing of the magnetoresistive sensor.

[0088] The encoder designed by the present invention is an absolute and linear encoder. The present invention senses the position change of the mover 1 through the magnetoresistive sensor, and on this basis, calculates the position information through the measurement result of the magnetoresistive sensor. The obtained position information is the 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.

[0089] Those skilled in the art should understand that the embodiments of the present application can be provided as methods, systems, or computer program products. Therefore, the present application can adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware aspects. Moreover, the present application can adopt the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk memories, CD-ROMs, optical memories, etc.) containing computer-usable program codes.

[0090] This application is described with reference to the flowcharts and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the present application. It should be understood that each flow and / or block in the flowcharts and / or block diagrams, and combinations of flows and / or blocks in the flowcharts and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to the processors of general-purpose computers, special-purpose computers, embedded processors, or other programmable data processing devices to produce a machine, such that the instructions executed by the processors of the computer or other programmable data processing devices generate means for implementing the functions specified in the Figure 1 one or more flows and / or blocks Figure 1 one or more blocks.

[0091] These computer program instructions can also be stored in a computer-readable memory that can direct a computer or other programmable data processing device to work in a specific manner, such that the instructions stored in the computer-readable memory produce a manufactured article including instruction means that implement the functions specified in the Figure 1 one or more flows and / or blocks Figure 1 one or more blocks.

[0092] These computer program instructions can also be loaded onto a computer or other programmable data processing device, such that a series of operation steps are executed on the computer or other programmable device to produce a computer-implemented process, so that the instructions executed on the computer or other programmable device provide steps for implementing the functions specified in the Figure 1 one or more flows and / or blocks Figure 1 one or more blocks.

[0093] Obviously, the above embodiments are only examples for clear illustration and are not limitations on the implementation manners. For those of ordinary skill in the art, other different forms of changes or variations can be made based on the above description. It is not necessary and impossible to enumerate all the implementation manners here. And the obvious changes or variations derived therefrom are still within the protection scope of the present invention.

Claims

1. An encoder based on the magnetoresistive principle, characterized in that, Comprising: A magnetic plate, fixed on the rotor of the motor, with uniformly distributed permanent magnets thereon; A plurality of magnetoresistive sensors, fixed on the stator of the motor, the spacing of the magnetoresistive sensors being the same as the pole pitch between the N pole and the S pole of the permanent magnets, and the magnetoresistive sensors being placed in the magnetic field of the magnetic plate; the magnetic field of the magnetic plate moves with the rotor of the motor, and the magnetoresistive sensors convert the magnetic field change into a sine signal and a cosine signal; An operational amplifier circuit, the sine signal and the cosine signal output by the magnetoresistive sensors are connected to the operational amplifier circuit, and the sine signal and the cosine signal are respectively converted into digital quantities after being conditioned and amplified; A processor, the sine signal and the cosine signal passing through the operational amplifier circuit are connected to the processor, the tangent signal of the electrical angle is calculated according to the sine signal and the cosine signal, and the tangent signal of the electrical angle is fitted to obtain the electrical angle value, and the value range of the electrical angle value is 0° to 90°; The electrical angle value is extended to 0° to 360° in combination with the sign of the digital quantity: 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 extended electrical angle value is the current electrical angle value falling 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 extended electrical angle value is the current electrical angle value falling 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 extended electrical angle value is the current electrical angle value falling 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 extended electrical angle value is the current electrical angle value falling within the fourth quadrant; The extended electrical angle value is the angle corresponding to the sector position where the magnetic plate is located, and the position information is obtained according to the corresponding relationship between the sector position where the magnetic plate is located and the spacing of the magnetoresistive sensors.

2. The encoder based on the magnetoresistive principle according to claim 1, characterized in that: It further 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 sensors are 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 sensors.

3. An encoder measurement method based on the magnetoresistance principle, characterized in that: When using the encoder based on the magnetoresistive principle described in claim 1 or 2, when the magnetoresistive sensors convert 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 supply voltage of the magnetoresistive chip of the magnetoresistive sensor, and k1 is the coefficient of the amplitude of the output signal of the magnetoresistive chip.

4. The encoder measurement method based on the magnetoresistive principle according to claim 3, wherein: Converting the sine signal and the cosine signal into digital quantities after being conditioned and amplified respectively includes: Performing voltage amplification and bias processing on the sine signal and the cosine signal, and the sine signal and the cosine signal after voltage amplification and bias processing are: V output = k2 * V sensor + V ref , Among them, V output is the sine signal and cosine signal after voltage amplification and bias processing, V sensor is the amplitude of the sine signal and cosine signal, k2 is the amplification factor, V ref is the reference bias voltage; The sine signal and the cosine signal after voltage amplification and bias processing are respectively converted into digital quantities through an analog-to-digital converter.

5. The encoder measurement method based on the magnetoresistive principle according to claim 3, characterized in that: 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.

6. The encoder measurement method based on the magnetoresistive principle according to claim 3, 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 Where 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.

7. The encoder measurement method based on the magnetoresistive principle according to claim 3, characterized in that: The position information is obtained according to the corresponding relationship between the sector position where the magnetic plate is located and the spacing of the magnetoresistive sensors, specifically as follows: S = D / 360 * θ '', where S is the position information finally measured by the encoder based on the magnetoresistive principle, D is the spacing of the magnetoresistive sensors, and θ '' is the angle corresponding to the sector position where the magnetic plate is located.

8. An encoder measurement system based on the magnetoresistive principle, characterized in that, It includes: The encoder based on the magnetoresistive principle, data acquisition module, signal conditioning and conversion module, and position information calculation module described in claim 1 or 2, The data acquisition module is used to receive the sine signal and cosine signal output by the magnetoresistive sensors, 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 respectively 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 calculate the tangent signal of the electrical angle according to the sine signal and cosine signal, fit the tangent signal of the electrical angle to obtain the electrical angle value, and the value range of the electrical angle value is 0° to 90°; Expand the electrical angle value to 0° to 360° in combination with the sign of the digital quantity: 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 falling in 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 falling in 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 falling in 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 falling in the fourth quadrant; The expanded electrical angle value is the angle corresponding to the sector position where the magnetic plate is located, and the position information is obtained according to the corresponding relationship between the sector position where the magnetic plate is located and the spacing of the magnetoresistive sensors.

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