Method and device for measuring three-degree-of-freedom displacement of equiphase Hall sensor

Abstract

The invention discloses an equiphase Hall sensor three-degree-of-freedom displacement measurement method and equipment, and belongs to the field of motors, and the equiphase Hall sensor three-degree-of-freedom displacement measurement equipment comprises a Halbach planar magnet, a Hall sensor, a signal processing system, a magnetic suspension planar motor and a feedback control system. The equal-phase Hall sensor three-degree-of-freedom displacement measurement method comprises the following steps: determining the arrangement of a Hall sensor in a magnetic suspension planar motor; the Hall sensor measures the magnetic field intensity passing through the position through the Hall effect; converting the measured magnetic field intensity into a magnetic field phase through a four-quadrant arc tangent method; establishing a relationship between a magnetic field phase and displacement according to magnetic field characteristics of the magnet; processing four groups of Hall sensor data, and calculating a motor rotation angle; displacement data measured by the Hall sensor are fed back to a control system of the motor in real time. According to the invention, the displacement of the magnetic suspension planar motor is accurately measured by using the equal-phase Hall sensor array in combination with the four-quadrant arc tangent method.

Description

Technical Field

[0001] The invention belongs to the field of motors, and in particular relates to a three-degree-of-freedom displacement measurement method and equipment of an equal-phase Hall sensor. Background Art

[0002] The permanent magnet synchronous planar motor is a device that can perform planar 6-DOF motion through electromagnetic drive. Due to its advantages such as no friction, high thrust density, easy lightweight and simple structure, it is widely used in high-end IC manufacturing, ultra-precision machining and biomedical fields.

[0003] The displacement measurement accuracy of the permanent magnet synchronous planar motor rotor will directly affect the subsequent control accuracy of the motor. Existing magnetic levitation planar motors use Hall sensors to measure the displacement of the motor and perform subsequent current calculations. The Hall sensor measures the sinusoidal magnetic field strength and obtains the linearly changing magnetic field phase through the four-quadrant inverse tangent method. The measurement accuracy of the Hall sensor is different within a complete magnetic field cycle. If two sensors with inconsistent accuracy are used for displacement calculation, the subsequent control accuracy will decrease.

[0004] With regard to the problem of inconsistent measurement accuracy of different Hall sensors under different magnetic field displacements in the existing technology for measuring the planar displacement of permanent magnet synchronous motors, no good solution has been proposed so far. Summary of the invention

[0005] The purpose of this section is to summarize some aspects of embodiments of the present invention and briefly introduce some preferred embodiments. Some simplifications or omissions may be made in this section and the specification abstract and the invention title of this application to avoid blurring the purpose of this section, the specification abstract and the invention title, and such simplifications or omissions cannot be used to limit the scope of the present invention.

[0006] In view of the above or existing problems of the three-degree-of-freedom displacement measurement method and device of the equal-phase Hall sensor, the present invention is proposed.

[0007] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0008] An embodiment of the present invention provides a method for measuring three-degree-of-freedom displacement of an equal-phase Hall sensor, comprising: determining the arrangement of the Hall sensor in a magnetic levitation planar motor; the Hall sensor measures the magnetic field strength passing through its position through the Hall effect; converting the magnetic field strength measured by two Hall chips into a magnetic field phase through a four-quadrant inverse tangent method; establishing a relationship between the magnetic field phase and the displacement according to the magnetic field distribution characteristics of a Halbach planar magnet; processing four sets of Hall sensor data to calculate the motor rotation angle; and feeding back the displacement data measured by the Hall sensor to the control system of the motor in real time.

[0009] As a preferred solution of the three-degree-of-freedom displacement measurement method of equal-phase Hall sensors described in the present invention, wherein: in the magnetic levitation planar motor, the arrangement of the Hall sensors is determined, including: arranging multiple Hall sensors in the X-axis and Y-axis directions, each group of sensors is composed of two Hall chips, and the interval between the Hall sensors is an integer multiple of the magnetic field period to ensure that the magnetic field changes received by the sensor are consistent and periodic; the two Hall chips in each group of Hall sensors measure the magnetic field strength at the same position, and the measured magnetic fields are in different directions, such as the X direction and the Y direction.

[0010] As a preferred solution of the equal-phase Hall sensor three-degree-of-freedom displacement measurement method described in the present invention, wherein: the Hall sensor measures the magnetic field strength passing through its position through the Hall effect, including: when the Hall sensor passes through the magnetic field, the Hall chip generates a voltage signal proportional to the magnetic field strength, assuming that the magnetic field strengths measured by the two Hall chips are H1 and H2 respectively, and the analog signal output by the Hall chip is converted into a digital signal through an analog-to-digital converter.

[0011] As a preferred solution of the equal-phase Hall sensor three-degree-of-freedom displacement measurement method of the present invention, wherein: the magnetic field intensity measured by the two Hall chips is converted into a magnetic field phase by a four-quadrant inverse tangent method, including:

[0012] According to the magnetic field strength H1 and H2 measured by the two Hall chips, the inverse tangent function is used to calculate the magnetic field phase :

[0013]

[0014] in, is the magnetic field phase.

[0015] As a preferred solution of the three-degree-of-freedom displacement measurement method of the equal-phase Hall sensor of the present invention, wherein: the relationship between the magnetic field phase and the displacement is established according to the magnetic field distribution characteristics of the Halbach plane magnet, including:

[0016] Using the relationship between the magnetic field phase and the magnetic field period, the displacement x of the Hall sensor can be calculated:

[0017]

[0018] Where x is the displacement of the Hall sensor in the magnetic field, τ n is the pole pitch of the Halbach planar magnet array;

[0019] Then, two Hall sensors with the same measuring direction are arranged in the same direction at an interval L, where L=n*T, n is a positive integer, and T is the period of the Halbach planar magnet array.

[0020] As a preferred solution of the equal-phase Hall sensor three-degree-of-freedom displacement measurement method of the present invention, the processing of four sets of Hall sensor data and calculation of the motor angle includes:

[0021] The displacement of the planar motor is calculated using the data measured by four sets of Hall sensors. The expression is as follows:

[0022]

[0023] Among them, X is the displacement of the magnetic levitation planar motor in the X direction, Y is the displacement of the magnetic levitation planar motor in the Y direction, and x 1 、x 2 ,y 1 ,y 2 are the displacement values ​​measured by four groups of Hall sensors, α is the rotation angle of the magnetic levitation planar motor in the plane motion, l x is the distance between two Hall sensors in the X direction, l y is the distance between two Hall sensors in the Y direction.

[0024] As a preferred solution of the equal-phase Hall sensor three-degree-of-freedom displacement measurement method described in the present invention, the displacement data measured by the Hall sensor is fed back to the control system of the motor in real time, including: for multiple groups of Hall sensors such as two sensors in the X and Y directions, data fusion technology is used to fuse the displacement data of multiple sensors into a single displacement information, different weights are assigned according to the accuracy and reliability of each sensor, and then the final displacement in each direction is obtained by weighted average; according to the displacement data fed back by the Hall sensor, the control system calculates the target position that the motor needs to reach in real time, for example, through a PID control algorithm, the target position and the current displacement are compared in real time, a corresponding control signal is generated, and the drive of the motor is adjusted.

[0025] A three-degree-of-freedom displacement measuring device using an equal-phase Hall sensor comprises: the three-degree-of-freedom displacement measuring device using an equal-phase Hall sensor comprises a Halbach planar magnet, a Hall sensor, a signal processing system, a magnetically suspended planar motor and a feedback control system.

[0026] As a preferred solution of the equal-phase Hall sensor three-degree-of-freedom displacement measurement device described in the present invention, wherein: the Halbach planar magnet includes a main magnet, a secondary magnet and a magnetic field distribution, the magnetic field strength generated by the array is uniform and periodic, and is used to generate a magnetic field change signal reflecting the displacement of the motor when the planar motor moves; the Hall sensor includes a Hall chip and a sensor arrangement, and the Hall sensor measures the magnetic field strength passing through the sensor position through its Hall effect principle, calculates the magnetic field phase according to the magnetic field strength value, and thus infers the displacement; the magnetic levitation planar motor includes a coil array and a suspension control system, and the magnetic levitation planar motor cooperates with the Hall sensor measurement system, and the magnetic levitation planar motor accurately controls its movement in the X and Y directions and the rotation angle α in the plane to achieve precise control of the three degrees of freedom.

[0027] As a preferred solution of the equal-phase Hall sensor three-degree-of-freedom displacement measurement device described in the present invention, the signal processing system includes a signal acquisition module and a data processing module, and the signal processing system is responsible for calculating the displacement of the motor in the X and Y directions according to the sensor position and the magnetic field phase, and inferring the motor's rotation angle α; the feedback control system adjusts the motor motion state in real time according to the displacement information measured by the Hall sensor array.

[0028] The beneficial effects of the present invention are as follows: the present invention can accurately measure the displacement of the magnetic levitation planar motor by using an array of equal-phase Hall sensors and processing the magnetic field strength in combination with the four-quadrant inverse tangent method. Through the joint measurement of two Hall chips, the high-precision magnetic field phase is calculated, thereby obtaining the displacement information of the planar motor in the X and Y directions, achieving millimeter-level or even higher precision displacement measurement, and meeting high-precision control requirements. The measurement accuracy is improved only by designing the spacing between the two groups of Hall sensors to be equal to the magnetic field period size, without increasing the number of sensors or changing the sensor data processing method. Since multiple Hall sensors are used and their data are fused, even if individual sensors are affected by the external environment or other factors, the reliability of the overall system can still be guaranteed. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative labor. Among them:

[0030] Figure 1 A flowchart of a three-degree-of-freedom displacement measurement method of an equal-phase Hall sensor provided in an embodiment of the present invention.

[0031] Figure 2 A schematic diagram of the arrangement of equal-phase Hall sensors in a magnetically levitated planar motor provided in an embodiment of the present invention.

[0032] The reference numerals in the drawings are: 6 - Halbach magnet array, 7 - mover, 8 - X-direction Hall sensor one, 9 - X-direction Hall sensor two, 10 - Y-direction Hall sensor one, 11 - Y-direction Hall sensor two. DETAILED DESCRIPTION

[0033] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the accompanying drawings.

[0034] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein, and those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0035] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The term "in one embodiment" that appears in different places in this specification does not necessarily refer to the same embodiment, nor does it refer to a separate or selective embodiment that is mutually exclusive with other embodiments.

[0036] Example 1

[0037] Reference Figure 1~Figure 2 , is an embodiment of the present invention, such as Figure 1 FIG. 1 is a flow chart of a method for measuring three-degree-of-freedom displacement of an equal-phase Hall sensor, comprising:

[0038] S1: Determine the arrangement of Hall sensors in a magnetically levitated planar motor.

[0039] Preferably, multiple Hall sensors are arranged in the X-axis and Y-axis directions, each group of sensors consists of two Hall chips, and the interval between the Hall sensors is an integer multiple of the magnetic field period to ensure that the magnetic field changes received by the sensor are consistent and periodic;

[0040] The two Hall chips in each set of Hall sensors measure the magnetic field strength at the same position, and the measured magnetic fields are in different directions, such as the X direction and the Y direction.

[0041] Furthermore, the sensor array needs to be arranged according to the magnetic field strength distribution generated by the Halbach magnet array. Each group of Hall sensors consists of two Hall chips, and the intervals between the sensors are integer multiples of the magnetic field period T to ensure that the magnetic field changes they measure are consistent and periodic.

[0042] The specific arrangement is as follows:

[0043] Two groups of Hall sensors are arranged in the X-axis direction of the motor. The two Hall chips of each group of sensors measure along the X direction, and their interval is T (one cycle of the magnetic field). Assuming T is the magnetic field period of the Halbach planar magnet array, the interval between the two groups of Hall sensors along the X direction is T;

[0044] X-axis Hall sensor 1: located at position x1, measuring the magnetic field in the X-axis direction;

[0045] X-axis Hall sensor 2: located at position x2, measuring the magnetic field in the X-axis direction;

[0046] Two groups of Hall sensors are arranged in the Y-axis direction, each group is composed of two Hall chips, and the interval between them is the magnetic field period T to maintain consistent magnetic field periodicity;

[0047] Y-axis Hall sensor 1: located at position y1, measuring the magnetic field in the Y-axis direction,

[0048] Y-axis Hall sensor 2: located at position y2, measuring the magnetic field in the Y-axis direction;

[0049] The two Hall chips in each set of Hall sensors measure the magnetic field strength at the same position, and the directions of the measured magnetic fields are different, corresponding to the components in the X-axis and Y-axis directions respectively. Specifically:

[0050] X-direction measurement: X-direction Hall sensor 1 and X-direction Hall sensor 2 are located at different positions x1 and x2 in the X direction respectively. Each Hall chip can sense the magnetic field changes related to the magnet array.

[0051] Y-direction measurement: Similarly, Y-direction Hall sensor 1 and Y-direction Hall sensor 2 are located at different positions y1 and y2 in the Y direction, and each Hall chip measures the magnetic field changes related to the Y axis;

[0052] The displacement value x in the X direction is calculated from the magnetic field phase measured by the Hall sensors 1 and 2 in the X direction; the displacement value y in the Y direction is calculated from the magnetic field phase measured by the Hall sensors 1 and 2 in the Y direction.

[0053] S2: Hall sensor measures the strength of the magnetic field passing through its location through the Hall effect.

[0054] Preferably, when the Hall sensor passes through a magnetic field, the Hall chip generates a voltage signal proportional to the magnetic field strength. Assuming that the magnetic field strengths measured by the two Hall chips are H1 and H2 respectively, the analog signal output by the Hall chip is converted into a digital signal through an analog-to-digital converter.

[0055] S3: The magnetic field intensity measured by the two Hall chips is converted into a magnetic field phase through the four-quadrant inverse tangent method.

[0056] Preferably, the magnetic field phase is calculated using the inverse tangent function according to the magnetic field strengths H1 and H2 measured by the two Hall chips. :

[0057]

[0058] in, is the magnetic field phase.

[0059] Further, assuming that H1 is the magnetic field strength measured by the first Hall chip (such as the X-axis direction), H2 is the magnetic field strength measured by the second Hall chip (such as the Y-axis direction), and assuming that the following two magnetic field strengths have been measured by the Hall sensor:

[0060] If H1=0.5 A / m, H2=0.8 A / m,

[0061] Use the inverse tangent function to compute the phase:

[0062] =atan2(H2,H1) Substitute the above H1 and H2 values ​​into the formula: =atan2(0.8,0.5),

[0063] Standard calculation using the inverse tangent function:

[0064] ≈atan2(0.8,0.5)≈1.038 rad;

[0065] The inverse tangent function atan2(H2,H1) will automatically determine the correct quadrant based on the signs of H1 and H2. For example:

[0066] If both H1 and H2 are positive, the phase of the result is in the first quadrant;

[0067] If H1 is negative, the result may be in the second or third quadrant;

[0068] If H2 is negative, the result is likely to be in the third or fourth quadrant.

[0069] S4: According to the magnetic field distribution characteristics of the Halbach planar magnet, a relationship is established between the magnetic field phase and the displacement.

[0070] Preferably, the displacement x of the Hall sensor is calculated using the relationship between the magnetic field phase and the magnetic field period:

[0071]

[0072] Where x is the displacement of the Hall sensor in the magnetic field, and τn is the pole pitch of the Halbach planar magnet array;

[0073] Then, two Hall sensors with the same measuring direction are arranged in the same direction at an interval L, where L=n*T, n is a positive integer, and T is the period of the Halbach planar magnet array.

[0074] Furthermore, the magnetic field strength H1 and H2 measured by the Hall sensor are used to calculate the magnetic field phase using the four-quadrant inverse tangent method. , =atan2(H2,H1). For example:

[0075] Assume that the magnetic field strength measured by the first Hall chip is H1=0.5 A / m. The magnetic field strength measured by the second Hall chip is H2=0.8 A / m.

[0076] The calculated magnetic field phase is:

[0077] =atan2(0.8,0.5)≈1.038 rad;

[0078] According to the above formula, using the magnetic field phase The relationship between the pole distance τn is used to infer the displacement x of the Hall sensor in the magnetic field.

[0079] Assuming the pole pitch of the Halbach magnet array is τn=1.5 cm:

[0080] x= ⋅τn=1.038⋅0.015≈0.00247 m=0.247 cm;

[0081] Therefore, the magnetic field phase obtained by measuring , the displacement of the Hall sensor in the magnetic field can be calculated;

[0082] In order to measure the displacement of the motor more accurately, multiple Hall sensors can be arranged in the same direction (such as X direction or Y direction). Assume that the interval between the Hall sensors is L=n⋅T, where n is a positive integer, indicating the interval multiple of the Hall sensor, and T is the period of the Halbach magnet array;

[0083] Assume that the period of the Halbach magnet array is T=5 cm, and select n=2 to arrange two Hall sensors, that is, the interval between the sensors is:

[0084] L=2⋅T=2⋅5 cm=10 cmL;

[0085] After such arrangement, the interval between the two Hall sensors is 10 cm, which can ensure good accuracy in long-distance displacement measurement.

[0086] S5: Process four sets of Hall sensor data and calculate the motor angle.

[0087] Preferably, the data measured by the four sets of Hall sensors are used to calculate the displacement of the planar motor, and the expression is as follows:

[0088]

[0089] Among them, X is the displacement of the magnetic levitation planar motor in the X direction, Y is the displacement of the magnetic levitation planar motor in the Y direction, and x 1 、x 2 ,y 1 ,y 2 are the displacement values ​​measured by four groups of Hall sensors, α is the rotation angle of the magnetic levitation planar motor in the plane motion, l x is the distance between two Hall sensors in the X direction, l y is the distance between two Hall sensors in the Y direction.

[0090] Furthermore, four sets of Hall sensors are arranged on the magnetic levitation planar motor to measure the displacement of the motor in the X and Y directions respectively.

[0091] X direction sensor data:

[0092] X-axis Hall sensor 1: x1=1.8 cm, X-axis Hall sensor 2: x2=2.0 cm, sensor spacing: lx=3.0 cm;

[0093] Y direction sensor data:

[0094] Y-axis Hall sensor 1: y1=2.2 cm, Y-axis Hall sensor 2: y2=2.0 cm, sensor spacing: ly=3.0 cm;

[0095] Calculate the X-direction displacement

[0096] Calculate the displacement in the X direction according to the formula:

[0097] X=(1.8 cm+2.0 cm) / 2=1.9 cm;

[0098] Calculate the Y-direction displacement

[0099] Calculate the displacement in the Y direction according to the formula:

[0100] Y=(2.2 cm+2.0 cm) / 2=2.1 cm;

[0101] Calculate the displacement difference in the X direction:

[0102] (x2-x1) / lx=(2.0 cm-1.8 cm) / 3.0 cm=0.0667

[0103] Calculate the displacement difference in the Y direction:

[0104] (y2-y1) / ly=(2.0 cm-2.2 cm) / 3.0 cm3=-0.0667

[0105] Calculate the rotation angle α:

[0106] α=0.0667+(-0.0667)=0;

[0107] Since α=0, it means that the rotation angle of the motor has not changed relative to the initial position, or it can be considered that the motor is moving smoothly.

[0108] S6: The displacement data measured by the Hall sensor is fed back to the motor control system in real time.

[0109] Preferably, for multiple groups of Hall sensors, such as two sensors in the X and Y directions, data fusion technology is used to fuse the displacement data of multiple sensors into a single displacement information, and different weights are assigned according to the accuracy and reliability of each sensor, and then the final displacement in each direction is obtained by weighted average;

[0110] Based on the displacement data fed back by the Hall sensor, the control system calculates the target position that the motor needs to reach in real time. For example, through the PID control algorithm, it compares the target position and the current displacement in real time, generates a corresponding control signal, and adjusts the drive of the motor.

[0111] Furthermore, assuming that the displacement data measured by the Hall sensor in each direction (X and Y) is x 1 ,x 2 , (X direction) and y 1 ,y 2 (Y direction), different weights w are assigned to each sensor according to its accuracy and reliability 1 ,w 2 (X direction) and w 3 ,w 4 (Y direction), and then calculate the final displacement information by weighted average;

[0112] Weighted average displacement in the X direction:

[0113]

[0114] Weighted average displacement in the Y direction:

[0115]

[0116] Among them, w 1 ,w 2 are the weights of X-axis Hall sensor 1 and X-axis Hall sensor 2, respectively, 3 ,w 4 are the weights of Y-axis Hall sensor 1 and Y-axis Hall sensor 2, respectively. fused and Y fused are the weighted average displacements in the X and Y directions, respectively;

[0117] Weight w 1 ,w 2， w 3 ,w 4 The selection is based on the accuracy and reliability of each sensor. If a sensor has higher accuracy (e.g., smaller error), it can be given a greater weight; if a sensor has poor stability or fails, its weight should be reduced;

[0118] The control system uses the PID algorithm to calculate the current displacement X fused , Y fused and target displacement X target ,Y target Calculate the control signal required for the motor to reach the target position,

[0119] First, calculate the error between the current displacement and the target displacement:

[0120] Error X =X target -X fused

[0121] Error Y =Y target -Y fused

[0122] Error X (t),Error Y (t) are the errors in the X and Y directions respectively;

[0123] The calculation formula of PID control is:

[0124]

[0125] Among them, U X (t) and U Y (t) are the control signals in the X and Y directions, respectively. Kp, Ki, and Kd are the proportional, integral, and differential gains of the PID control, respectively.

[0126] The X-axis Hall sensor 1 and sensor 2 measure displacements x1 and x2, the Y-axis Hall sensor 1 and sensor 2 measure displacements y1 and y2, and the weighted average displacement X in the X direction is calculated. fused Calculate the weighted average displacement Y in the Y direction fused， Set target position X target ,Y target ; Calculate the error in the X and Y directions Error X and Error Y , calculate the control signal U according to the PID formula X (t) and U Y (t) The control signal U X (t) and U Y (t) is sent to the motor drive module to adjust the position of the motor. The system provides real-time feedback on the current position of the motor and continues to adjust the drive signal until the motor reaches the target position.

[0127] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A three-degree-of-freedom displacement measurement method using an equal-phase Hall sensor, characterized in that: include: Determine the arrangement of Hall sensors in a magnetically levitated planar motor; Hall sensors measure the strength of the magnetic field passing through their location through the Hall effect; The magnetic field intensity measured by the two Hall chips is converted into the magnetic field phase by the four-quadrant inverse tangent method; According to the magnetic field distribution characteristics of Halbach planar magnet, the relationship between magnetic field phase and displacement is established; Process four sets of Hall sensor data and calculate the motor angle; The displacement data measured by the Hall sensor is fed back to the motor control system in real time; The method of converting the magnetic field intensity measured by the two Hall chips into a magnetic field phase by using the four-quadrant inverse tangent method includes: According to the magnetic field strength H1 and H2 measured by the two Hall chips, the inverse tangent function is used to calculate the magnetic field phase : ； in, is the magnetic field phase.

2. The three-degree-of-freedom displacement measurement method of the equal-phase Hall sensor according to claim 1, characterized in that: Determining the arrangement of the Hall sensors in the magnetically suspended planar motor comprises: In the X-axis and Y-axis directions, multiple Hall sensors are arranged. Each group of sensors consists of two Hall chips. The interval between the Hall sensors is an integer multiple of the magnetic field period to ensure that the magnetic field changes received by the sensor are consistent and periodic. The two Hall chips of each set of Hall sensors measure the magnetic field strength at the same position, and the measured magnetic fields are in different directions, including the X direction and the Y direction.

3. The three-degree-of-freedom displacement measurement method of the equal-phase Hall sensor according to claim 1, characterized in that: The Hall sensor measures the strength of the magnetic field passing through its location through the Hall effect, including: When the Hall sensor passes through a magnetic field, the Hall chip generates a voltage signal proportional to the magnetic field strength. Assuming that the magnetic field strengths measured by the two Hall chips are H1 and H2 respectively, the analog signal output by the Hall chip is converted into a digital signal through an analog-to-digital converter.

4. The three-degree-of-freedom displacement measurement method of the equal-phase Hall sensor according to claim 1, characterized in that: The relationship between the magnetic field phase and the displacement is established according to the magnetic field distribution characteristics of the Halbach planar magnet, including: Using the relationship between the magnetic field phase and the magnetic field period, the displacement x of the Hall sensor can be calculated: ； Where x is the displacement of the Hall sensor in the magnetic field, τ n is the pole pitch of the Halbach planar magnet array; Then, two Hall sensors with the same measuring direction are arranged in the same direction at an interval L, where L=n*T, n is a positive integer, and T is the period of the Halbach planar magnet array.

5. The three-degree-of-freedom displacement measurement method of the equal-phase Hall sensor according to claim 1, characterized in that: The processing of four sets of Hall sensor data and calculation of the motor angle includes: The displacement of the planar motor is calculated using the data measured by four sets of Hall sensors. The expression is as follows: ； Among them, X is the displacement of the magnetic levitation planar motor in the X direction, Y is the displacement of the magnetic levitation planar motor in the Y direction, x1, x2, y1, y2 are the displacement values ​​measured by four groups of Hall sensors, α is the rotation angle of the magnetic levitation planar motor in the plane motion, l x is the distance between two Hall sensors in the X direction, l y is the distance between two Hall sensors in the Y direction.

6. The three-degree-of-freedom displacement measurement method of the equal-phase Hall sensor according to claim 1, characterized in that: The displacement data measured by the Hall sensor is fed back to the control system of the motor in real time, including: For multiple groups of Hall sensors, including two sensors in the X and Y directions, data fusion technology is used to fuse the displacement data of multiple sensors into a single displacement information. Different weights are assigned according to the accuracy and reliability of each sensor, and then the final displacement in each direction is obtained by weighted average. Based on the displacement data fed back by the Hall sensor, the control system calculates the target position that the motor needs to reach in real time, including using the PID control algorithm to compare the target position and current displacement in real time, generate corresponding control signals, and adjust the motor drive.

7. A three-degree-of-freedom displacement measurement device using an equal-phase Hall sensor, used to implement the method described in any one of claims 1 to 6, characterized in that: The equal-phase Hall sensor three-degree-of-freedom displacement measurement device comprises a Halbach planar magnet, a Hall sensor, a signal processing system, a magnetic suspension planar motor and a feedback control system.

8. The equal-phase Hall sensor three-degree-of-freedom displacement measurement device according to claim 7, characterized in that: The Halbach planar magnet includes a main magnet, a secondary magnet and a magnetic field distribution. The magnetic field strength generated by the array is uniform and periodic, and is used to generate a magnetic field change signal reflecting the displacement of the motor when the planar motor moves; The Hall sensor comprises a Hall chip and a sensor arrangement. The Hall sensor measures the magnetic field strength passing through the sensor position through its Hall effect principle, calculates the magnetic field phase according to the magnetic field strength value, and thus infers the displacement; The magnetic levitation planar motor comprises a coil array and a levitation control system. The magnetic levitation planar motor accurately controls its movement in the X and Y directions and the rotation angle α in the plane, thereby achieving accurate control of three degrees of freedom.

9. The equal-phase Hall sensor three-degree-of-freedom displacement measurement device according to claim 7, characterized in that: The signal processing system includes a signal acquisition module and a data processing module. The signal processing system is responsible for calculating the displacement of the motor in the X and Y directions and inferring the rotation angle α of the motor according to the sensor position and the magnetic field phase. The feedback control system adjusts the motor motion state in real time according to the displacement information measured by the Hall sensor array.

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