Radial stator sensor online correction method for magnetic suspension molecular pump

Abstract

The application discloses a kind of magnetic suspension molecular pump radial stator sensor online correction method, it belongs to the field of sensor correction, its technical points are in at:Step a, main shaft is attached to the first, second radial protection bearing position, and main shaft is at 0, 45, 90, 135, 180, 225, 270, 315 position direction When recording the voltage value of each sensor respectively;Step b, each sensor is corrected: each sensor can obtain eight groups of voltage value, air gap length relationship data, by fitting according to linear relationship of voltage value, air gap length realizes the online correction of each sensor.The technical scheme of the application can realize the online correction of radial stator sensor.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of sensor correction, and more particularly, to a method for online correction of a radial stator sensor of a magnetic levitation molecular pump. BACKGROUND

[0002] The zero point of the magnetic levitation molecular pump is the basis in the magnetic levitation molecular pump, which determines the reference position of the main shaft of the molecular pump during high-speed operation. Other key indicators of the magnetic levitation system in the magnetic levitation molecular pump are calculated based on the zero point position, so the zero point position is crucial in the entire magnetic levitation system.

[0003] In the magnetic levitation stator bearing, the sensor assembly includes 4 XY sensors, 4 AB sensors, and 2 Z-direction sensors. For the 4 XY sensors and the 4 AB sensors, the voltage signal is directly measured. Then the distance value is output according to the voltage-distance curve. Then the position of the main shaft is obtained according to the distance output by each sensor.

[0004] For the "voltage-distance" curves of the above-mentioned 4 XY sensors and 4 AB sensors, as described in CN116086300B, each sensor needs to be calibrated offline separately, that is, the electrical signal of the sensor is obtained at different distances, and then the voltage-distance curve is obtained.

[0005] The above-mentioned method has the following disadvantages:

[0006] (1) The 8 sensors need to be corrected one by one, and the correction efficiency is relatively low.

[0007] (2) Offline correction and actual measurement correspond to different objects. That is, offline correction is not corrected by the main shaft. Therefore, the "voltage-distance" curve obtained by offline correction is not necessarily completely applicable to the main shaft.

[0008] (3) Temperature error. Offline correction and actual measurement are at different temperatures, which will inevitably bring temperature error.

[0009] In summary, a new technical route needs to be studied. SUMMARY

[0010] The purpose of the present application is to overcome the shortcomings of the prior art and provide a method for online correction of a stator sensor of a magnetic levitation molecular pump.

[0011] The technical solution of the present application is as follows:

[0012] A kind of magnetic suspension molecular pump radial stator sensor online correction method, the radial stator from top to bottom sequentially includes: first radial protection bearing, first radial displacement sensor, XY magnetic bearing, motor, AB magnetic bearing, second radial displacement sensor, second radial protection bearing;

[0013] XY magnetic bearing includes: X+ direction magnetic pole pair, Y+ direction magnetic pole pair, X- direction magnetic pole pair, Y- direction magnetic pole pair;

[0014] AB magnetic bearing includes: A+ direction magnetic pole pair, B+ direction magnetic pole pair, A- direction magnetic pole pair, B- direction magnetic pole pair;

[0015] First radial displacement sensor includes: X+ sensor, Y+ sensor, X- sensor, Y- sensor;

[0016] Second radial displacement sensor includes: A+ sensor, B+ sensor, A- sensor, B- sensor;

[0017] It includes the following steps:

[0018] Step a, the spindle is attached to the first, second radial protection bearing position, and the spindle is at 0 °, 45 °, 90 °, 135 °, 180 °, 225 °, 270 °, 315 ° position direction respectively Record the voltage value of each sensor;

[0019] The definition of the spindle at any angle α is that the center axis of the first radial protection bearing, the center axis of the spindle, the projection of the spindle only in the direction of X+, A+ direction magnetic pole pair is moved to the same horizontal plane respectively G point, F point, initial line, the angle between the initial line and GF line counterclockwise is α;α is any one of 0 °, 45 °, 90 °, 135 °, 180 °, 225 °, 270 °, 315 °;

[0020] Step b, each sensor is corrected: each sensor can obtain eight groups of voltage values, air gap length relationship data, and the voltage value, air gap length is fitted according to linear relationship to realize the online correction of each sensor.

[0021] Further, the inner diameter of the XY, AB magnetic bearing is k1, k2 respectively;The inner diameter of the first, second radial protection bearing is n1, n2 respectively;The outer diameter of the spindle is m;

[0022] When the spindle is at any angle α position direction:

[0023] The air gap length corresponding to X+ sensor is: 0.5k1-0.5 (n1-m) cos α-0.5 (m 2 - ((n1-m) sin α) 2 ) 0.5 ;

[0024] The air gap length corresponding to the Y+ sensor is: 0.5k1-0.5(n1-m)cos(α+π / 2)-0.5(m 2 -((n1-m)sin(α+π / 2)) 2 0.5 ;

[0025] The air gap length corresponding to the X- sensor is: 0.5k1-0.5(n1-m)cos(α+π)-0.5(m 2 -((n1-m)sin(α+π)) 2 0.5 ;

[0026] The air gap length corresponding to the Y- sensor is: 0.5k1-0.5(n1-m)cos(α-π / 2)-0.5(m 2 -((n1-m)sin(α-π / 2)) 2 0.5 ;

[0027] The air gap length corresponding to the A+ sensor is: 0.5k2-0.5(n2-m)cosα-0.5(m 2 -((n2-m)sinα) 2 0.5 ;

[0028] The air gap length corresponding to the B+ sensor is: 0.5k2-0.5(n2-m)cos(α+π / 2)-0.5(m 2 -((n2-m)sin(α+π / 2)) 2 0.5 ;

[0029] The air gap length corresponding to the A- sensor is: 0.5k2-0.5(n2-m)cos(α+π)-0.5(m 2 -((n2-m)sin(α+π)) 2 0.5 ;

[0030] The air gap length corresponding to the B- sensor is: 0.5k2-0.5(n2-m)cos(α-π / 2)-0.5(m 2 -((n2-m)sin(α-π / 2)) 2 0.5 .

[0031] Further, the method further comprises: step c, correcting the linear relationship;

[0032] The voltage-distance relationship of each sensor obtained in step b is expressed as:​​​​​​​

[0033] X+ sensor: y = kix + di;

[0034] Y+ sensor: y = k2x + d2;

[0035] X- sensor: y = k3x + d3;

[0036] Y- sensor: y = k4x + d4;

[0037] A+ sensor: y = k5x + d5;

[0038] B+ sensor: y = k6x + d6;

[0039] A- sensor: y = k7x + d7;

[0040] B- sensor: y = k8x + d8;

[0041] First, the following 8 coordinate points are used to fit a circle:

[0042] ((k4Y - 1 + d4 - k2Y + 1 - d2) / 2, (k3X - 1 + d3 - k1X + 1 - di) / 2);

[0043] ((k4Y - 2 + d4 - k2Y + 2 - d2) / 2, (k3X - 2 + d3 - k1X + 2 - di) / 2);

[0044] ((k4Y - 3 + d4 - k2Y + 3 - d2) / 2, (k3X - 3 + d3 - k1X + 3 - di) / 2);

[0045] ((k4Y - 4 + d4 - k2Y + 4 - d2) / 2, (k3X - 4 + d3 - k1X + 4 - di) / 2);

[0046] ((k4Y - 5 + d4 - k2Y + 5 - d2) / 2, (k3X - 5 + d3 - k1X + 5 - di) / 2);

[0047] ((k4Y - 6 + d4 - k2Y + 6 - d2) / 2, (k3X - 6 + d3 - k1X + 6 - di) / 2);

[0048] ((k4Y - 7 + d4 - k2Y + 7 - d2) / 2, (k3X - 7 + d3 - k1X + 7 - di) / 2);

[0049] ((k4Y - 8 + d4 - k2Y + 8 - d2) / 2, (k3X - 8 + d3 - k1X + 8 - di) / 2);

[0050] The center coordinates of the circle can be expressed as: (△u,△v);

[0051] Then, the linear relationship correction of the X+ sensor, the Y+ sensor, the X- sensor and the Y- sensor is:

[0052] X+ sensor: y=k1x+d1+△v;

[0053] Y+ sensor: y=k2x+d2+△u;

[0054] X- sensor: y=k3x+d3-△v;

[0055] Y- sensor: y=k4x+d4-△v;

[0056] Secondly, a circle is fitted by the following 8 points:

[0057] ((k8B-1+d8-k6B+1-d6) / 2, (k7A-1+d7-k5A+1-d5) / 2);

[0058] ((k8B-2+d8-k6B+2-d6) / 2, (k7A-2+d7-k5A+2-d5) / 2);

[0059] ((k8B-3+d8-k6B+3-d6) / 2, (k7A-3+d7-k5A+3-d5) / 2);

[0060] ((k8B-4+d8-k6B+4-d6) / 2, (k7A-4+d7-k5A+4-d5) / 2);

[0061] ((k8B-5+d8-k6B+5-d6) / 2, (k7A-5+d7-k5A+5-d5) / 2);

[0062] ((k8B-6+d8-k6B+6-d6) / 2, (k7A-6+d7-k5A+6-d5) / 2);

[0063] ((k8B-7+d8-k6B+7-d6) / 2, (k7A-7+d7-k5A+7-d5) / 2);

[0064] ((k8B-8+d8-k6B+8-d6) / 2, (k7A-8+d7-k5A+8-d5) / 2);

[0065] The center coordinates of the circle are expressed as: (△u', △v');

[0066] Then, the linear relationship correction of the A+ sensor, the B+ sensor, the A- sensor and the B- sensor is:

[0067] A+ sensor: y=k5x+d5+△v';

[0068] B+ sensor: y=k6x+d6+△u';

[0069] A- sensor: y=k7x+d7-△v';

[0070] B- sensor: y=k8x+d8-△u'.

[0071] A kind of magnetic suspension molecular pump radial stator sensor online correction method, the radial stator from top to bottom sequentially includes: first radial protection bearing, first radial displacement sensor, XY magnetic bearing, motor, AB magnetic bearing, second radial displacement sensor, second radial protection bearing;

[0072] XY magnetic bearing includes: X+ direction magnetic pole pair, Y+ direction magnetic pole pair, X- direction magnetic pole pair, Y- direction magnetic pole pair;

[0073] AB magnetic bearing includes: A+ direction magnetic pole pair, B+ direction magnetic pole pair, A- direction magnetic pole pair, B- direction magnetic pole pair;

[0074] First radial displacement sensor includes: X+ sensor, Y+ sensor, X- sensor, Y- sensor;

[0075] Second radial displacement sensor includes: A+ sensor, B+ sensor, A- sensor, B- sensor;

[0076] Wherein, the inner surface diameter of XY, AB magnetic bearing is respectively k1, k2;The inner surface diameter of first, second radial protection bearing is respectively n1, n2;The outer surface diameter of main shaft is m;

[0077] Phase angle: with X+ direction as zero degree, increase in phase angle counterclockwise rotation;

[0078] Including the following steps:

[0079] S100, 0° phase angle detection:

[0080] Only when X+ direction magnetic pole pair, A+ direction magnetic pole pair are energized, main shaft is attached to the position of first, second radial protection bearing, and the voltage values of X+ sensor, Y+ sensor, X- sensor, Y- sensor, A+ sensor, B+ sensor, A- sensor, B- sensor at this time are recorded, and are respectively recorded as: X+1, Y+1, X-1, Y-1, A+1, B+1, A-1, B-1;

[0081] S200, 45° phase angle detection: only when the X+ magnetic pole pair, Y- magnetic pole pair, A+ magnetic pole pair, and B- magnetic pole pair are energized, the main shaft is attached to the first and second radial protection bearing positions, and the voltage values of the X+ sensor, Y+ sensor, X- sensor, Y- sensor, A+ sensor, B+ sensor, A- sensor, and B- sensor at this time are recorded as X+2, Y+2, X-2, Y-2, A+2, B+2, A-2, and B-2, respectively.

[0082] S300, 90° phase angle detection: only when the Y- magnetic pole pair and B- magnetic pole pair are energized, the main shaft is attached to the first and second radial protection bearing positions, and the voltage values of the X+ sensor, Y+ sensor, X- sensor, Y- sensor, A+ sensor, B+ sensor, A- sensor, and B- sensor at this time are recorded as X+3, Y+3, X-3, Y-3, A+3, B+3, A-3, and B-3, respectively.

[0083] S400, 135° phase angle detection: only when the Y- magnetic pole pair, X- magnetic pole pair, B- magnetic pole pair, and A- magnetic pole pair are energized, the main shaft is attached to the first and second radial protection bearing positions, and the voltage values of the X+ sensor, Y+ sensor, X- sensor, Y- sensor, A+ sensor, B+ sensor, A- sensor, and B- sensor at this time are recorded as X+4, Y+4, X-4, Y-4, A+4, B+4, A-4, and B-4, respectively.

[0084] S500, 180° phase angle detection: only when the X- magnetic pole pair and A- magnetic pole pair are energized, the main shaft is attached to the first and second radial protection bearing positions, and the voltage values of the X+ sensor, Y+ sensor, X- sensor, Y- sensor, A+ sensor, B+ sensor, A- sensor, and B- sensor at this time are recorded as X+5, Y+5, X-5, Y-5, A+5, B+5, A-5, and B-5, respectively.

[0085] S600, 225° phase angle detection: only when the X- magnetic pole pair, Y+ magnetic pole pair, A- magnetic pole pair, and B+ magnetic pole pair are energized, the main shaft is attached to the first and second radial protection bearing positions, and the voltage values of the X+ sensor, Y+ sensor, X- sensor, Y- sensor, A+ sensor, B+ sensor, A- sensor, and B- sensor at this time are recorded as X+6, Y+6, X-6, Y-6, A+6, B+6, A-6, and B-6, respectively.

[0086] S700, 270° phase angle detection: only when the Y+ magnetic pole pair and the B+ magnetic pole pair are energized, the main shaft is attached to the first and second radial protection bearing positions, and the voltage values of the X+ sensor, Y+ sensor, X- sensor, Y- sensor, A+ sensor, B+ sensor, A- sensor, and B- sensor at this time are recorded as X+7, Y+7, X-7, Y-7, A+7, B+7, A-7, and B-7, respectively.

[0087] S800, 315° phase angle detection: only when the Y+ magnetic pole pair, X+ magnetic pole pair, B+ magnetic pole pair, and A+ magnetic pole pair are energized, the main shaft is attached to the first and second radial protection bearing positions, and the voltage values of the X+ sensor, Y+ sensor, X- sensor, Y- sensor, A+ sensor, B+ sensor, A- sensor, and B- sensor at this time are recorded as X+8, Y+8, X-8, Y-8, A+8, B+8, A-8, and B-8, respectively.

[0088] S900, the voltage-distance relationship of the X+ sensor, Y+ sensor, X- sensor, Y- sensor, A+ sensor, B+ sensor, A- sensor, and B- sensor is fitted according to a linear relationship respectively:

[0089] y=kx+d, y represents the distance, x represents the voltage of the sensor, k is the slope, and d is the intercept;

[0090] The coordinates of the eight fitting points of the X+ sensor are:

[0091] (X+1, 0.5k1-0.5(n1-m)cos0°-0.5(m 2 -((n1-m)sin0°) 2 ) 0.5 );

[0092] (X+2, 0.5k1-0.5(n1-m)cos45°-0.5(m 2 -((n1-m)sin45°) 2 ) 0.5 );

[0093] (X+3, 0.5k1-0.5(n1-m)cos90°-0.5(m 2 -((n1-m)sin90°) 2 ) 0.5 );

[0094] (X+4, 0.5k1-0.5(n1-m)cos135°-0.5(m 2 -((n1-m)sin135°) 2 ) 0.5 );

[0095] (X+5, 0.5ki - 0.5(n1 - m)cos 180° - 0.5(m 2 - ((n1 - m)sin 180°) 2 ) 0.5 ) ;

[0096] (X+6, 0.5ki - 0.5(n1 - m)cos 225° - 0.5(m 2 - ((n1 - m)sin 225°) 2 ) 0.5 ) ;

[0097] (X+7, 0.5ki - 0.5(n1 - m)cos 270° - 0.5(m 2 - ((n1 - m)sin 270°) 2 ) 0.5 ) ;

[0098] (X+8, 0.5ki - 0.5(n1 - m)cos 315° - 0.5(m 2 - ((n1 - m)sin 315°) 2 ) 0.5 ) ;

[0099] The 8 fitted point coordinates of the Y+ sensor are:

[0100] (Y+1, 0.5ki - 0.5(n1 - m)cos 90° - 0.5(m 2 - ((n1 - m)sin 90°) 2 ) 0.5 ) ;

[0101] (Y+2, 0.5ki - 0.5(n1 - m)cos 135° - 0.5(m 2 - ((n1 - m)sin 135°) 2 ) 0.5 ) ;

[0102] (Y+3, 0.5ki - 0.5(n1 - m)cos 180° - 0.5(m 2 - ((n1 - m)sin 180°) 2 ) 0.5 ) ;

[0103] (Y+4, 0.5ki - 0.5(n1 - m)cos 225° - 0.5(m 2 - ((n1 - m)sin 225°) 2 ) 0.5 ) ;

[0104] (Y+5, 0.5ki - 0.5(n1 - m)cos270° - 0.5(m 2 - ((n1 - m)sin270°) 2 ) 0.5 ) ;

[0105] (Y+6, 0.5ki - 0.5(n1 - m)cos315° - 0.5(m 2 - ((n1 - m)sin315°) 2 ) 0.5 ) ;

[0106] (Y+7, 0.5ki - 0.5(n1 - m)cos0° - 0.5(m 2 - ((n1 - m)sin0°) 2 ) 0.5 ) ;

[0107] (Y+8, 0.5ki - 0.5(n1 - m)cos45° - 0.5(m 2 - ((n1 - m)sin45°) 2 ) 0.5 ) ;

[0108] The 8 fitted point coordinates of the X-sensor are:

[0109] (X-1, 0.5ki - 0.5(n1 - m)cos180° - 0.5(m 2 - ((n1 - m)sin180°) 2 ) 0.5 ) ;

[0110] (X-2, 0.5ki - 0.5(n1 - m)cos225° - 0.5(m 2 - ((n1 - m)sin225°) 2 ) 0.5 ) ;

[0111] (X-3, 0.5ki - 0.5(n1 - m)cos270° - 0.5(m 2 - ((n1 - m)sin270°) 2 ) 0.5 ) ;

[0112] (X-4, 0.5ki - 0.5(n1 - m)cos315° - 0.5(m 2 - ((n1 - m)sin315°) 2 ) 0.5 ) ;

[0113] (X-5, 0.5ki - 0.5(n1 - m)cos0° - 0.5(m 2 - ((n1 - m)sin0°) 2 ) 0.5 ) ;

[0114] (X-6, 0.5ki - 0.5(n1 - m)cos45° - 0.5(m 2 - ((n1 - m)sin45°) 2 ) 0.5 ) ;

[0115] (X-7, 0.5ki - 0.5(n1 - m)cos90° - 0.5(m 2 - ((n1 - m)sin90°) 2 ) 0.5 ) ;

[0116] (X-8, 0.5ki - 0.5(n1 - m)cos135° - 0.5(m 2 - ((n1 - m)sin135°) 2 ) 0.5 ) ;

[0117] The 8 fitting point coordinates of the Y-sensor are:

[0118] (Y-1, 0.5ki - 0.5(n1 - m)cos270° - 0.5(m 2 - ((n1 - m)sin270°) 2 ) 0.5 ) ;

[0119] (Y-2, 0.5ki - 0.5(n1 - m)cos315° - 0.5(m 2 - ((n1 - m)sin315°) 2 ) 0.5 ) ;

[0120] (Y-3, 0.5ki - 0.5(n1 - m)cos0° - 0.5(m 2 - ((n1 - m)sin0°) 2 ) 0.5 ) ;

[0121] (Y-4, 0.5ki - 0.5(n1 - m)cos45° - 0.5(m 2 - ((n1 - m)sin45°) 2 ) 0.5 ) ;

[0122] (Y-5, 0.5ki - 0.5(n1 - m)cos90° - 0.5(m2 -((n1-m)sin90°) 2 ) 0.5 );

[0123] (Y-6, 0.5k1-0.5(n1-m)cos135°-0.5(m 2 -((n1-m)sin135°) 2 ) 0.5 );

[0124] (Y-7, 0.5k1-0.5(n1-m)cos180°-0.5(m 2 -((n1-m)sin180°) 2 ) 0.5 );

[0125] (Y-8, 0.5k1-0.5(n1-m)cos225°-0.5(m 2 -((n1-m)sin225°) 2 ) 0.5 );

[0126] The 8 fitted point coordinates of the A+ sensor are:

[0127] (A+1, 0.5k2-0.5(n2-m)cos0°-0.5(m 2 -((n2-m)sin0°) 2 ) 0.5 );

[0128] (A+2, 0.5k2-0.5(n2-m)cos45°-0.5(m 2 -((n2-m)sin45°) 2 ) 0.5 );

[0129] (A+3, 0.5k2-0.5(n2-m)cos90°-0.5(m 2 -((n2-m)sin90°) 2 ) 0.5 );

[0130] (A+4, 0.5k2-0.5(n2-m)cos135°-0.5(m 2 -((n2-m)sin135°) 2 ) 0.5 );

[0131] (A+5, 0.5k2-0.5(n2-m)cos180°-0.5(m 2 -((n2-m)sin180°)2 ) 0.5 );

[0132] (A+6, 0.5k2-0.5(n2-m)cos225°-0.5(m 2 -((n2-m)sin225°) 2 ) 0.5 );

[0133] (A+7, 0.5k2-0.5(n2-m)cos270°-0.5(m 2 -((n2-m)sin270°) 2 ) 0.5 );

[0134] (A+8, 0.5k2-0.5(n2-m)cos315°-0.5(m 2 -((n2-m)sin315°) 2 ) 0.5 );

[0135] The 8 fitted point coordinates of the B+ sensor are:

[0136] (B+1, 0.5k2-0.5(n2-m)cos90°-0.5(m 2 -((n2-m)sin90°) 2 ) 0.5 );

[0137] (B+2, 0.5k2-0.5(n2-m)cos135°-0.5(m 2 -((n2-m)sin135°) 2 ) 0.5 );

[0138] (B+3, 0.5k2-0.5(n2-m)cos180°-0.5(m 2 -((n2-m)sin180°) 2 ) 0.5 );

[0139] (B+4, 0.5k2-0.5(n2-m)cos225°-0.5(m 2 -((n2-m)sin225°) 2 ) 0.5 );

[0140] (B+5, 0.5k2-0.5(n2-m)cos270°-0.5(m 2 -((n2-m)sin270°) 2 ) 0.5);

[0141] (B+6, 0.5k2-0.5(n2-m)cos315°-0.5(m 2 -((n2-m)sin315°) 2 ) 0.5 );

[0142] (B+7, 0.5k2-0.5(n2-m)cos0°-0.5(m 2 -((n2-m)sin0°) 2 ) 0.5 );

[0143] (B+8, 0.5k2-0.5(n2-m)cos45°-0.5(m 2 -((n2-m)sin45°) 2 ) 0.5 );

[0144] The 8 fitted point coordinates of A-sensor are:

[0145] (A-1, 0.5k2-0.5(n2-m)cos180°-0.5(m 2 -((n2-m)sin180°) 2 ) 0.5 );

[0146] (A-2, 0.5k2-0.5(n2-m)cos225°-0.5(m 2 -((n2-m)sin225°) 2 ) 0.5 );

[0147] (A-3, 0.5k2-0.5(n2-m)cos270°-0.5(m 2 -((n2-m)sin270°) 2 ) 0.5 );

[0148] (A-4, 0.5k2-0.5(n2-m)cos315°-0.5(m 2 -((n2-m)sin315°) 2 ) 0.5 );

[0149] (A-5, 0.5k2-0.5(n2-m)cos0°-0.5(m 2 -((n2-m)sin0°) 2 ) 0.5 );

[0150] (A-6, 0.5k2-0.5(n2-m)cos45°-0.5(m 2 -((n2-m)sin45°) 2 ) 0.5 );

[0151] (A-7, 0.5k2-0.5(n2-m)cos90°-0.5(m 2 -((n2-m)sin90°) 2 ) 0.5 );

[0152] (A-8, 0.5k2-0.5(n2-m)cos135°-0.5(m 2 -((n2-m)sin135°) 2 ) 0.5 );

[0153] B-8 fitted point coordinates of the sensor are:

[0154] (B-1, 0.5k2-0.5(n2-m)cos270°-0.5(m 2 -((n2-m)sin270°) 2 ) 0.5 );

[0155] (B-2, 0.5k2-0.5(n2-m)cos315°-0.5(m 2 -((n2-m)sin315°) 2 ) 0.5 );

[0156] (B-3, 0.5k2-0.5(n2-m)cos0°-0.5(m 2 -((n2-m)sin0°) 2 ) 0.5 );

[0157] (B-4, 0.5k2-0.5(n2-m)cos45°-0.5(m 2 -((n2-m)sin45°) 2 ) 0.5 );

[0158] (B-5, 0.5k2-0.5(n2-m)cos90°-0.5(m 2 -((n2-m)sin90°) 2 ) 0.5 );

[0159] (B-6, 0.5k2-0.5(n2-m)cos135°-0.5(m2 - ((n2 - m) sin 135°) 2 0.5

[0160] (B-7, 0.5k2-0.5(n2-m)cos180°-0.5(m 2 - ((n2 - m) sin 180°) 2 0.5

[0161] (B-8, 0.5k2-0.5(n2-m)cos225°-0.5(m 2 - ((n2 - m) sin 225°) 2 0.5

[0162] Further, the current flowing through the coils of the four pole pairs in steps S200, S400, S600, S800 is kept the same.

[0163] Further, the current flowing through the X+ pole pair, the Y- pole pair, the A+ pole pair, and the B- pole pair in S200 is the same.

[0164] Further, the current flowing through the Y- pole pair, the X- pole pair, the B- pole pair, and the A- pole pair in S400 is the same.

[0165] Further, the current flowing through the X- pole pair, the Y+ pole pair, the A- pole pair, and the B+ pole pair in S600 is the same.

[0166] Further, the current flowing through the Y+ pole pair, the X+ pole pair, the B+ pole pair, and the A+ pole pair in S800 is the same.

[0167] Further, the method further comprises: S1000, correcting the linear relationship;

[0168] The voltage value-distance relationship of each sensor is expressed as:

[0169] X+ sensor: y = k1x + d1;

[0170] Y+ sensor: y = k2x + d2;

[0171] X- sensor: y = k3x + d3;

[0172] Y- sensor: y = k4x + d4;

[0173] A+ sensor: y = k5x + d5;

[0174] B+ sensor: y = k6x + d6; ​​​​​​

[0175] A-sensor: y = k7x + d7;

[0176] B-sensor: y = k8x + d8;

[0177] First, the following 8 coordinate points are fitted to a circle:

[0178] ((k4Y - 1 + d4 - k2Y + 1 - d2) / 2, (k3X - 1 + d3 - k1X + 1 - d1) / 2);

[0179] ((k4Y - 2 + d4 - k2Y + 2 - d2) / 2, (k3X - 2 + d3 - k1X + 2 - d1) / 2);

[0180] ((k4Y - 3 + d4 - k2Y + 3 - d2) / 2, (k3X - 3 + d3 - k1X + 3 - d1) / 2);

[0181] ((k4Y - 4 + d4 - k2Y + 4 - d2) / 2, (k3X - 4 + d3 - k1X + 4 - d1) / 2);

[0182] ((k4Y - 5 + d4 - k2Y + 5 - d2) / 2, (k3X - 5 + d3 - k1X + 5 - d1) / 2);

[0183] ((k4Y - 6 + d4 - k2Y + 6 - d2) / 2, (k3X - 6 + d3 - k1X + 6 - d1) / 2);

[0184] ((k4Y - 7 + d4 - k2Y + 7 - d2) / 2, (k3X - 7 + d3 - k1X + 7 - d1) / 2);

[0185] ((k4Y - 8 + d4 - k2Y + 8 - d2) / 2, (k3X - 8 + d3 - k1X + 8 - d1) / 2);

[0186] The center coordinates of the circle can be expressed as: (△u,△v);

[0187] Then, the linear relationship of the X+ sensor, Y+ sensor, X- sensor, and Y- sensor is corrected as:

[0188] X+ sensor: y = k1x + d1 +△v;

[0189] Y+ sensor: y = k2x + d2 +△u;

[0190] X- sensor: y = k3x + d3 -△v;

[0191] Y- sensor: y = k4x + d4 -△v;

[0192] Secondly, a circle is fitted by the following 8 points:

[0193] ((k8B-1+d8-k6B+1-d6) / 2, (k7A-1+d7-k5A+1-d5) / 2);

[0194] ((k8B-2+d8-k6B+2-d6) / 2, (k7A-2+d7-k5A+2-d5) / 2);

[0195] ((k8B-3+d8-k6B+3-d6) / 2, (k7A-3+d7-k5A+3-d5) / 2);

[0196] ((k8B-4+d8-k6B+4-d6) / 2, (k7A-4+d7-k5A+4-d5) / 2);

[0197] ((k8B-5+d8-k6B+5-d6) / 2, (k7A-5+d7-k5A+5-d5) / 2);

[0198] ((k8B-6+d8-k6B+6-d6) / 2, (k7A-6+d7-k5A+6-d5) / 2);

[0199] ((k8B-7+d8-k6B+7-d6) / 2, (k7A-7+d7-k5A+7-d5) / 2);

[0200] ((k8B-8+d8-k6B+8-d6) / 2, (k7A-8+d7-k5A+8-d5) / 2);

[0201] The center coordinates of the circle can be expressed as: (△u', △v');

[0202] Then, the linear relationship correction of the A+ sensor, the B+ sensor, the A- sensor and the B- sensor is:

[0203] A+ sensor: y=k5x+d5+△v';

[0204] B+ sensor: y=k6x+d6+△u';

[0205] A- sensor: y=k7x+d7-△v';

[0206] B- sensor: y=k8x+d8-△u'.

[0207] The application has the following advantages:

[0208] (1) The application proposes a magnetic suspension molecular pump radial stator sensor online correction method. By controlling the energization of 8 magnetic pole pairs, the spindle records the voltage values of 8 sensors at 0°, 45°, 90°, 135°, 180°, 225°, 270°, and 315° positions. The calibration of 8 sensors can be completed at one time, improving the efficiency of calibration.

[0209] (2) Eight sets of voltage value and air gap length data can be obtained for each sensor. The online correction of each sensor is realized by fitting the voltage value and air gap length according to the linear relationship.

[0210] That is, the inner surface diameters of the XY and AB magnetic bearings are k1 and k2 respectively; the inner surface diameters of the first and second radial protection bearings are n1 and n2 respectively; and the outer surface diameter of the spindle is m;

[0211] When the spindle is at an arbitrary angle α position direction:

[0212] The air gap length corresponding to the X+ sensor is: 0.5k1-0.5(n1-m)cosα-0.5(m 2 -((n1-m)sinα) 2 ) 0.5 ;

[0213] The air gap length corresponding to the Y+ sensor is: 0.5k1-0.5(n1-m)cos(α+π / 2)-0.5(m 2 -((n1-m)sin(α+π / 2)) 2 ) 0.5 ;

[0214] The air gap length corresponding to the X- sensor is: 0.5k1-0.5(n1-m)cos(α+π)-0.5(m 2 -((n1-m)sin(α+π)) 2 ) 0.5 ;

[0215] The air gap length corresponding to the Y- sensor is: 0.5k1-0.5(n1-m)cos(α-π / 2)-0.5(m 2 -((n1-m)sin(α-π / 2)) 2 ) 0.5 ;

[0216] The air gap length corresponding to the A+ sensor is: 0.5k2-0.5(n2-m)cosα-0.5(m 2 -((n2-m)sinα) 2 ) 0.5 ;

[0217] B+ sensor corresponding air gap length: 0.5k2-0.5(n2-m)cos(α+π / 2)-0.5(m 2 -((n2-m)sin(α+π / 2)) 2 ) 0.5 ;

[0218] A- sensor corresponding air gap length: 0.5k2-0.5(n2-m)cos(α+π)-0.5(m 2 -((n2-m)sin(α+π)) 2 ) 0.5 ;

[0219] B- sensor corresponding air gap length: 0.5k2-0.5(n2-m)cos(α-π / 2)-0.5(m 2 -((n2-m)sin(α-π / 2)) 2 ) 0.5 .

[0220] (3) the center trajectory of the main shaft should be a circle around the radial protection bearing. Based on this, the radial stator sensor online correction method of the aforementioned magnetic suspension molecular pump is further modified, and the position information of the main shaft calculated after the modification is more accurate. BRIEF DESCRIPTION OF DRAWINGS

[0221] The application will be further described in detail below with reference to the embodiments in the drawings, but it does not constitute any limitation on the application.

[0222] Figure 1 is the pole pair distribution plan view of the XY magnetic bearing.

[0223] Figure 2 is the horizontal projection view of the main shaft, the XY magnetic bearing and the first radial protection bearing.

[0224] Figure 3 is the main shaft state diagram (XY magnetic bearing) when measured for the first time.

[0225] Figure 4 is the main shaft state diagram (XY magnetic bearing) when measured for the second time.

[0226] Figure 5 is the main shaft state diagram (XY magnetic bearing) when measured for the third time.

[0227] Figure 6 is the main shaft state diagram (XY magnetic bearing) when measured for the fourth time.

[0228] Figure 7 is the spindle state diagram (XY magnetic bearing) at the fifth measurement.

[0229] Figure 8 is the spindle state diagram (XY magnetic bearing) at the sixth measurement.

[0230] Figure 9 is the spindle state diagram (XY magnetic bearing) at the seventh measurement.

[0231] Figure 10 is the spindle state diagram (XY magnetic bearing) at the eighth measurement.

[0232] Figure 11 is the theoretical center point trajectory of the spindle.

[0233] The reference signs are explained as follows:

[0234] The inner surface of the XY magnetic bearing in the projection on the horizontal plane line 100;

[0235] The first radial protection bearing in the projection on the horizontal plane line 200;

[0236] The outer diameter of the spindle in the projection on the horizontal plane line 300;

[0237] The center axis of the spindle in the projection trajectory on the horizontal plane line 400. DETAILED DESCRIPTION

[0238] In order to make the purpose, technical scheme and advantages of the present application clearer, the technical scheme of the present application will be described clearly and completely below in combination with the specific embodiments of the present application and corresponding drawings. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0239] <Explanation of the radial stator>

[0240] For the magnetic levitation molecular pump, the radial stator includes, from top to bottom in sequence: the first radial protection bearing, the first radial displacement sensor, the XY magnetic bearing, the motor, the AB magnetic bearing, the second radial displacement sensor, and the second radial protection bearing.

[0241] The inner surface diameters of the XY and AB magnetic bearings are k1 and k2 respectively; the inner surface diameters of the first and second radial protection bearings are n1 and n2 respectively.

[0242] The outer surface diameter of the spindle inserted in the radial stator is m.

[0243] The XY magnetic bearing comprises, in sequence clockwise, an X+ magnetic pole pair, a Y+ magnetic pole pair, an X- magnetic pole pair, and a Y- magnetic pole pair, which are denoted as a first magnetic pole pair, a second magnetic pole pair, a third magnetic pole pair, and a fourth magnetic pole pair.

[0244] The AB magnetic bearing comprises, in sequence clockwise, an A+ magnetic pole pair, a B+ magnetic pole pair, an A- magnetic pole pair, and a B- magnetic pole pair, which are denoted as a fifth magnetic pole pair, a sixth magnetic pole pair, a seventh magnetic pole pair, and an eighth magnetic pole pair.

[0245] The first radial displacement sensor comprises an X+ sensor, a Y+ sensor, an X- sensor, and a Y- sensor, which are denoted as a first sensor, a second sensor, a third sensor, and a fourth sensor.

[0246] The second radial displacement sensor comprises an A+ sensor, a B+ sensor, an A- sensor, and a B- sensor, which are denoted as a fifth sensor, a sixth sensor, a seventh sensor, and an eighth sensor.

[0247] It should be noted that, for any jth magnetic pole pair, it corresponds to the jth sensor, and j is any natural number from 1 to 8.

[0248] It should be noted that the jth magnetic pole pair corresponds to the j+4th magnetic pole pair.

[0249] <Embodiment I: A radial stator sensor online correction method for a magnetic suspension molecular pump>

[0250] A radial stator sensor online correction method for a magnetic suspension molecular pump comprises the following steps:

[0251] S100, first measurement:

[0252] Only when the X+ magnetic pole pair and the A+ magnetic pole pair are energized, the main shaft is attached to the positions of the first and second radial protection bearings under the attraction of the XY magnetic bearing and the AB magnetic bearing at this time.

[0253] At this time, the voltage values of the X+ sensor, the Y+ sensor, the X- sensor, the Y- sensor, the A+ sensor, the B+ sensor, the A- sensor, and the B- sensor are denoted as X+1, Y+1, X-1, Y-1, A+1, B+1, A-1, and B-1.

[0254] At this time, the air gap lengths corresponding to the X+ direction, the Y+ direction, the X- direction, the Y- direction, the A+ direction, the B+ direction, the A- direction, and the A- direction are (k1-n1) / 2, 0.5k1-0.5(m 2 -(n1-m) 2 ) 0.5 , 0.5(k1+n1)-m, 0.5k1-0.5(m 2 -(n1-m)2 0.5 , (k2-n2) / 2, 0.5k2-0.5(m 2 -(n2-m) 2 0.5 , 0.5(k2+n2)-m, 0.5k2-0.5(m 2 -(n2-m) 2 0.5

[0255] That is, the first measurement can obtain the sensor voltage value-gap length matrix as:

[0256]

[0257] S200, only for X+ to the magnetic pole pair, Y- to the magnetic pole pair, A+ to the magnetic pole pair, B- to the magnetic pole pair energized, the main shaft is pasted on the first, second radial protection bearing position, record X+ sensor, Y+ sensor, X- sensor, Y- sensor, A+ sensor, B+ sensor, A- sensor, B- sensor at this time Voltage value, respectively recorded as: X+2, Y+2, X-2, Y-2, A+2, B+2, A-2, B-2;

[0258] The second measurement can obtain the sensor voltage value-gap length matrix as:

[0259]

[0260] S300, only for Y- to the magnetic pole pair, B- to the magnetic pole pair energized, the main shaft is pasted on the first, second radial protection bearing position, record X+ sensor, Y+ sensor, X- sensor, Y- sensor, A+ sensor, B+ sensor, A- sensor, B- sensor at this time Voltage value, respectively recorded as: X+3, Y+3, X-3, Y-3, A+3, B+3, A-3, B-3;

[0261] The third measurement can obtain the sensor voltage value-gap length matrix as:

[0262]

[0263] S400, only for Y- to the magnetic pole pair, X- to the magnetic pole pair, B- to the magnetic pole pair, A- to the magnetic pole pair energized, the main shaft is pasted on the first, second radial protection bearing position, record X+ sensor, Y+ sensor, X- sensor, Y- sensor, A+ sensor, B+ sensor, A- sensor, B- sensor at this time Voltage value, respectively recorded as: X+4, Y+4, X-4, Y-4, A+4, B+4, A-4, B-4;

[0264] ​​​​​​​The fourth measurement can obtain the sensor voltage value-gap length matrix as follows:

[0265] ;

[0266] S500, only when the X-direction magnetic pole pair and the A-direction magnetic pole pair are energized, the main shaft is attached to the first and second radial protection bearing positions, and the voltage values of the X+ sensor, Y+ sensor, X- sensor, Y- sensor, A+ sensor, B+ sensor, A- sensor and B- sensor at this time are recorded as X+5, Y+5, X-5, Y-5, A+5, B+5, A-5 and B-5, respectively.

[0267] The fifth measurement can obtain the sensor voltage value-gap length matrix as follows:

[0268] ;

[0269] S600, only when the X-direction magnetic pole pair, Y+ magnetic pole pair, A- direction magnetic pole pair and B+ magnetic pole pair are energized, the main shaft is attached to the first and second radial protection bearing positions, and the voltage values of the X+ sensor, Y+ sensor, X- sensor, Y- sensor, A+ sensor, B+ sensor, A- sensor and B- sensor at this time are recorded as X+6, Y+6, X-6, Y-6, A+6, B+6, A-6 and B-6, respectively.

[0270] The sixth measurement can obtain the sensor voltage value-gap length matrix as follows:

[0271] ;

[0272] S700, only when the Y+ direction magnetic pole pair and B+ direction magnetic pole pair are energized, the main shaft is attached to the first and second radial protection bearing positions, and the voltage values of the X+ sensor, Y+ sensor, X- sensor, Y- sensor, A+ sensor, B+ sensor, A- sensor and B- sensor at this time are recorded as X+7, Y+7, X-7, Y-7, A+7, B+7, A-7 and B-7, respectively.

[0273] The seventh measurement can obtain the sensor voltage value-gap length matrix as follows:

[0274] ;

[0275] S800, only when the Y+ direction magnetic pole pair, the X+ direction magnetic pole pair, the B+ direction magnetic pole pair and the A+ direction magnetic pole pair are energized, the main shaft is attached to the first and second radial protection bearing positions, and the voltage values of the X+ sensor, the Y+ sensor, the X- sensor, the Y- sensor, the A+ sensor, the B+ sensor, the A- sensor and the B- sensor at this time are recorded as X+8, Y+8, X-8, Y-8, A+8, B+8, A-8 and B-8 respectively;

[0276] The sensor voltage value-gap length matrix obtained by the eighth measurement is as follows:

[0277] ;

[0278] The first column of the sensor voltage value-gap length matrix obtained by the first to eighth measurements is the voltage value read by the sensor, and the second column is the gap length corresponding to the sensor in the first column.

[0279] S900, after the eight measurements are completed, the X+ sensor, the Y+ sensor, the X- sensor, the Y- sensor, the A+ sensor, the B+ sensor, the A- sensor and the B- sensor are calibrated.

[0280] The above eight sensors are fitted by using a linear relationship: y=kx+d, where y represents the distance, x represents the voltage of the sensor, k is the slope, and d is the intercept. It should be noted that y=kx+d here is only used to illustrate that the voltage-distance curve of the eight sensors can be represented by a linear relationship, and k and d fitted by the eight sensors are not the same. That is, for each sensor, k and d correspond to each sensor.

[0281] The coordinates of the eight fitting points of the X+ sensor are as follows:

[0282] (X+1, 0.5k1-0.5(n1-m)cos0°-0.5(m 2 -((n1-m)sin0°) 2 ) 0.5 );

[0283] (X+2, 0.5k1-0.5(n1-m)cos45°-0.5(m 2 -((n1-m)sin45°) 2 ) 0.5 );

[0284] (X+3, 0.5k1-0.5(n1-m)cos90°-0.5(m 2 -((n1-m)sin90°) 2 ) 0.5 );

[0285] (X+4, 0.5ki - 0.5(n1 - m)cos135° - 0.5(m 2 - ((n1 - m)sin135°) 2 ) 0.5 ) ;

[0286] (X+5, 0.5ki - 0.5(n1 - m)cos180° - 0.5(m 2 - ((n1 - m)sin180°) 2 ) 0.5 ) ;

[0287] (X+6, 0.5ki - 0.5(n1 - m)cos225° - 0.5(m 2 - ((n1 - m)sin225°) 2 ) 0.5 ) ;

[0288] (X+7, 0.5ki - 0.5(n1 - m)cos270° - 0.5(m 2 - ((n1 - m)sin270°) 2 ) 0.5 ) ;

[0289] (X+8, 0.5ki - 0.5(n1 - m)cos315° - 0.5(m 2 - ((n1 - m)sin315°) 2 ) 0.5 ) ;

[0290] The 8 fitted point coordinates of the Y+ sensor are:

[0291] (Y+1, 0.5ki - 0.5(n1 - m)cos90° - 0.5(m 2 - ((n1 - m)sin90°) 2 ) 0.5 ) ;

[0292] (Y+2, 0.5ki - 0.5(n1 - m)cos135° - 0.5(m 2 - ((n1 - m)sin135°) 2 ) 0.5 ) ;

[0293] (Y+3, 0.5ki - 0.5(n1 - m)cos180° - 0.5(m 2 - ((n1 - m)sin180°) 2 ) 0.5 ) ;

[0294] (Y+4, 0.5ki - 0.5(n1 - m)cos225° - 0.5(m 2 - ((n1 - m)sin225°) 2 ) 0.5 ) ;

[0295] (Y+5, 0.5ki - 0.5(n1 - m)cos270° - 0.5(m 2 - ((n1 - m)sin270°) 2 ) 0.5 ) ;

[0296] (Y+6, 0.5ki - 0.5(n1 - m)cos315° - 0.5(m 2 - ((n1 - m)sin315°) 2 ) 0.5 ) ;

[0297] (Y+7, 0.5ki - 0.5(n1 - m)cos0° - 0.5(m 2 - ((n1 - m)sin0°) 2 ) 0.5 ) ;

[0298] (Y+8, 0.5ki - 0.5(n1 - m)cos45° - 0.5(m 2 - ((n1 - m)sin45°) 2 ) 0.5 ) ;

[0299] The 8 fitted point coordinates of the X-sensor are:

[0300] (X-1, 0.5ki - 0.5(n1 - m)cos180° - 0.5(m 2 - ((n1 - m)sin180°) 2 ) 0.5 ) ;

[0301] (X-2, 0.5ki - 0.5(n1 - m)cos225° - 0.5(m 2 - ((n1 - m)sin225°) 2 ) 0.5 ) ;

[0302] (X-3, 0.5ki - 0.5(n1 - m)cos270° - 0.5(m 2 - ((n1 - m)sin270°) 2 ) 0.5 ) ;

[0303] (X-4, 0.5ki - 0.5(n1 - m)cos315° - 0.5(m 2 - ((n1 - m)sin315°) 2 ) 0.5 ) ;

[0304] (X-5, 0.5ki - 0.5(n1 - m)cos0° - 0.5(m 2 - ((n1 - m)sin0°) 2 ) 0.5 ) ;

[0305] (X-6, 0.5ki - 0.5(n1 - m)cos45° - 0.5(m 2 - ((n1 - m)sin45°) 2 ) 0.5 ) ;

[0306] (X-7, 0.5ki - 0.5(n1 - m)cos90° - 0.5(m 2 - ((n1 - m)sin90°) 2 ) 0.5 ) ;

[0307] (X-8, 0.5ki - 0.5(n1 - m)cos135° - 0.5(m 2 - ((n1 - m)sin135°) 2 ) 0.5 ) ;

[0308] The 8 fitting point coordinates of the Y-sensor are:

[0309] (Y-1, 0.5ki - 0.5(n1 - m)cos270° - 0.5(m 2 - ((n1 - m)sin270°) 2 ) 0.5 ) ;

[0310] (Y-2, 0.5ki - 0.5(n1 - m)cos315° - 0.5(m 2 - ((n1 - m)sin315°) 2 ) 0.5 ) ;

[0311] (Y-3, 0.5ki - 0.5(n1 - m)cos0° - 0.5(m 2 - ((n1 - m)sin0°) 2 ) 0.5 ) ;

[0312] (Y-4, 0.5ki - 0.5(n1 - m)cos45° - 0.5(m2 - ((n1-m)sin45°) 2 ) 0.5 );

[0313] (Y-5, 0.5k1-0.5(n1-m)cos90°-0.5(m 2 - ((n1-m)sin90°) 2 ) 0.5 );

[0314] (Y-6, 0.5k1-0.5(n1-m)cos135°-0.5(m 2 - ((n1-m)sin135°) 2 ) 0.5 );

[0315] (Y-7, 0.5k1-0.5(n1-m)cos180°-0.5(m 2 - ((n1-m)sin180°) 2 ) 0.5 );

[0316] (Y-8, 0.5k1-0.5(n1-m)cos225°-0.5(m 2 - ((n1-m)sin225°) 2 ) 0.5 );

[0317] The 8 fitted point coordinates of the A+ sensor are:

[0318] (A+1, 0.5k2-0.5(n2-m)cos0°-0.5(m 2 - ((n2-m)sin0°) 2 ) 0.5 );

[0319] (A+2, 0.5k2-0.5(n2-m)cos45°-0.5(m 2 - ((n2-m)sin45°) 2 ) 0.5 );

[0320] (A+3, 0.5k2-0.5(n2-m)cos90°-0.5(m 2 - ((n2-m)sin90°) 2 ) 0.5 );

[0321] (A+4, 0.5k2-0.5(n2-m)cos135°-0.5(m 2 - ((n2-m)sin135°)2 ) 0.5 );

[0322] (A+5, 0.5k2-0.5(n2-m)cos 180°-0.5(m 2 -((n2-m)sin 180°) 2 ) 0.5 );

[0323] (A+6, 0.5k2-0.5(n2-m)cos 225°-0.5(m 2 -((n2-m)sin 225°) 2 ) 0.5 );

[0324] (A+7, 0.5k2-0.5(n2-m)cos 270°-0.5(m 2 -((n2-m)sin 270°) 2 ) 0.5 );

[0325] (A+8, 0.5k2-0.5(n2-m)cos 315°-0.5(m 2 -((n2-m)sin 315°) 2 ) 0.5 );

[0326] The 8 fitted point coordinates of B+ sensor are:

[0327] (B+1, 0.5k2-0.5(n2-m)cos 90°-0.5(m 2 -((n2-m)sin 90°) 2 ) 0.5 );

[0328] (B+2, 0.5k2-0.5(n2-m)cos 135°-0.5(m 2 -((n2-m)sin 135°) 2 ) 0.5 );

[0329] (B+3, 0.5k2-0.5(n2-m)cos 180°-0.5(m 2 -((n2-m)sin 180°) 2 ) 0.5 );

[0330] (B+4, 0.5k2-0.5(n2-m)cos 225°-0.5(m 2 -((n2-m)sin 225°) 2 ) 0.5) ;

[0331] (B+5, 0.5k2-0.5(n2-m)cos270°-0.5(m 2 -((n2-m)sin270°) 2 ) 0.5 ) ;

[0332] (B+6, 0.5k2-0.5(n2-m)cos315°-0.5(m 2 -((n2-m)sin315°) 2 ) 0.5 ) ;

[0333] (B+7, 0.5k2-0.5(n2-m)cos0°-0.5(m 2 -((n2-m)sin0°) 2 ) 0.5 ) ;

[0334] (B+8, 0.5k2-0.5(n2-m)cos45°-0.5(m 2 -((n2-m)sin45°) 2 ) 0.5 ) ;

[0335] The 8 fitted point coordinates of the A-sensor are:

[0336] (A-1, 0.5k2-0.5(n2-m)cos180°-0.5(m 2 -((n2-m)sin180°) 2 ) 0.5 ) ;

[0337] (A-2, 0.5k2-0.5(n2-m)cos225°-0.5(m 2 -((n2-m)sin225°) 2 ) 0.5 ) ;

[0338] (A-3, 0.5k2-0.5(n2-m)cos270°-0.5(m 2 -((n2-m)sin270°) 2 ) 0.5 ) ;

[0339] (A-4, 0.5k2-0.5(n2-m)cos315°-0.5(m 2 -((n2-m)sin315°) 2 ) 0.5 ) ;

[0340] (A-5, 0.5k2-0.5(n2-m)cos0°-0.5(m 2 -((n2-m)sin0°) 2 ) 0.5 );

[0341] (A-6, 0.5k2-0.5(n2-m)cos45°-0.5(m 2 -((n2-m)sin45°) 2 ) 0.5 );

[0342] (A-7, 0.5k2-0.5(n2-m)cos90°-0.5(m 2 -((n2-m)sin90°) 2 ) 0.5 );

[0343] (A-8, 0.5k2-0.5(n2-m)cos135°-0.5(m 2 -((n2-m)sin135°) 2 ) 0.5 );

[0344] B-8 fitted point coordinates of the sensor are:

[0345] (B-1, 0.5k2-0.5(n2-m)cos270°-0.5(m 2 -((n2-m)sin270°) 2 ) 0.5 );

[0346] (B-2, 0.5k2-0.5(n2-m)cos315°-0.5(m 2 -((n2-m)sin315°) 2 ) 0.5 );

[0347] (B-3, 0.5k2-0.5(n2-m)cos0°-0.5(m 2 -((n2-m)sin0°) 2 ) 0.5 );

[0348] (B-4, 0.5k2-0.5(n2-m)cos45°-0.5(m 2 -((n2-m)sin45°) 2 ) 0.5 );

[0349] (B-5, 0.5k2-0.5(n2-m)cos90°-0.5(m2 -((n2-m)sin90°) 2 ) 0.5 );

[0350] (B-6, 0.5k2-0.5(n2-m)cos135°-0.5(m 2 -((n2-m)sin135°) 2 ) 0.5 );

[0351] (B-7, 0.5k2-0.5(n2-m)cos180°-0.5(m 2 -((n2-m)sin180°) 2 ) 0.5 );

[0352] (B-8, 0.5k2-0.5(n2-m)cos225°-0.5(m 2 -((n2-m)sin225°) 2 ) 0.5 )。

[0353] It should be noted that for the XY magnetic bearing, the eight magnetic pole pairs are provided with coils.

[0354] The magnetic attraction force F of the magnetic pole pair is as follows:

[0355] F = 0.5 x I 2 x dL / dx; I is the current through the coil, L is the inductance of the coil, and x is the air gap distance. For the eight magnetic pole pairs of the magnetic suspension, the structure of the coils used is the same. Therefore, as long as the current I flowing through the coil is the same, the magnetic attraction force F of the magnetic pole pair spindle can be ensured to be the same.

[0356] Therefore, during the second, fourth, sixth, and eighth measurements, the currents of the four magnetic pole pairs are ensured to be the same. In this way, the spindle can be ensured to move in the direction of Figure 4 , Figure 6 , Figure 8 , Figure 10 , that is, 0° in the X positive direction, Figure 4 45°, Figure 6 135°, Figure 8 225°, Figure 10 315°.

[0357] <Example Two: A magnetic suspension molecular pump radial stator sensor online correction method>

[0358] In order to further accurately correct the eight displacement sensors,

[0359] The X+ sensor, Y+ sensor, X- sensor, Y- sensor, A+ sensor, B+ sensor, A- sensor, and B- sensor are calibrated:

[0360] The above eight sensors are sequentially fitted by linear relationship as follows:

[0361] The X+ sensor: y=k1x+d1;

[0362] The Y+ sensor: y=k2x+d2;

[0363] The X- sensor: y=k3x+d3;

[0364] The Y- sensor: y=k4x+d4;

[0365] The A+ sensor: y=k5x+d5;

[0366] The B+ sensor: y=k6x+d6;

[0367] The A- sensor: y=k7x+d7;

[0368] The B- sensor: y=k8x+d8.

[0369] As shown in Figure 11 , for the X+ sensor, Y+ sensor, X- sensor, and Y- sensor, the X+ direction is the N-axis positive direction, the Y+ direction is the E-axis positive direction, and the center of the first radial protection bearing is the coordinate origin.

[0370] The coordinates of the center of the main shaft are (E0, N0). When the main shaft contacts the first radial protection bearing, the shape of the outer surface of the main shaft can be expressed as:

[0371] (E-E0) 2 +(N-N0) 2 =m 2 ;

[0372] Let E=0, and the following can be solved:

[0373] N X+ =N0+(m 2 -E0 2 ) 0.5 ;

[0374] N X- =N0-(m 2 -E0 2 ) 0.5 ;

[0375] For the X+ sensor, the measured distance is L X+ , and for the X- sensor, the measured distance is L X- , so there are:

[0376] L X+ =0.5k1-[N0+(m 2 -E0 2 ) 0.5 ];L X- =N0-(m 2 -E0 2 ) 0.5 +0.5k1;

[0377] then N0=0.5(L X- -L X+ );

[0378] Correspondingly, for the Y+ sensor, the measured distance is L Y+ , for the X- sensor, the measured distance is L Y- . then E0=(L Y- -L Y+ ).

[0379] The inner surface of the first radial protection bearing is a circle, and the locus line 400 of the center coordinates of the main shaft in the eight states of 0°, 45°, 90°, 135°, 180°, 225°, 270° and 315° is also a circle.

[0380] That is, a circle is fitted through the following eight points:

[0381] ((k4Y-1+d4-k2Y+1-d2) / 2, (k3X-1+d3-k1X+1-d1) / 2);

[0382] ((k4Y-2+d4-k2Y+2-d2) / 2, (k3X-2+d3-k1X+2-d1) / 2);

[0383] ((k4Y-3+d4-k2Y+3-d2) / 2, (k3X-3+d3-k1X+3-d1) / 2);

[0384] ((k4Y-4+d4-k2Y+4-d2) / 2, (k3X-4+d3-k1X+4-d1) / 2);

[0385] ((k4Y-5+d4-k2Y+5-d2) / 2, (k3X-5+d3-k1X+5-d1) / 2);

[0386] ((k4Y-6+d4-k2Y+6-d2) / 2, (k3X-6+d3-k1X+6-d1) / 2);

[0387] ((k4Y-7+d4-k2Y+7-d2) / 2, (k3X-7+d3-k1X+7-d1) / 2);

[0388] ((k4Y-8+d4-k2Y+8-d2) / 2, (k3X-8+d3-k1X+8-d1) / 2);

[0389] The center of the circle can be expressed as: (△u,△v).

[0390] In theory, the center of the trajectory line 400 is the center of the first radial protection bearing. Therefore, the linear relationship of the X+ sensor, the Y+ sensor, the X- sensor, and the Y- sensor needs to be corrected as follows:

[0391] X+ sensor: y=k1x+d1+△v;

[0392] Y+ sensor: y=k2x+d2+△u;

[0393] X- sensor: y=k3x+d3-△v;

[0394] Y- sensor: y=k4x+d4-△v.

[0395] Similarly, for the A+ sensor, the B+ sensor, the A- sensor, and the B- sensor, a circle is also fitted through the following eight points:

[0396] ((k8B-1+d8-k6B+1-d6) / 2, (k7A-1+d7-k5A+1-d5) / 2);

[0397] ((k8B-2+d8-k6B+2-d6) / 2, (k7A-2+d7-k5A+2-d5) / 2);

[0398] ((k8B-3+d8-k6B+3-d6) / 2, (k7A-3+d7-k5A+3-d5) / 2);

[0399] ((k8B-4+d8-k6B+4-d6) / 2, (k7A-4+d7-k5A+4-d5) / 2);

[0400] ((k8B-5+d8-k6B+5-d6) / 2, (k7A-5+d7-k5A+5-d5) / 2);

[0401] ((k8B-6+d8-k6B+6-d6) / 2, (k7A-6+d7-k5A+6-d5) / 2);

[0402] ((k8B-7+d8-k6B+7-d6) / 2, (k7A-7+d7-k5A+7-d5) / 2);

[0403] ((k8B-8+d8-k6B+8-d6) / 2, (k7A-8+d7-k5A+8-d5) / 2);

[0404] The center coordinates of the circle can be expressed as: (△u', △v').

[0405] The linear relationship correction of the A+ sensor, the B+ sensor, the A- sensor, and the B- sensor is:

[0406] A+ sensor: y=k5x+d5+△v';

[0407] B+ sensor: y=k6x+d6+△u';

[0408] A- sensor: y=k7x+d7-△v';

[0409] B- sensor: y=k8x+d8-△u'.

[0410] The above-mentioned embodiments are the preferred embodiments of the present application, which are only used to facilitate the description of the present application and do not limit the present application in any form. Any person skilled in the art can make partial changes or modifications to the equivalent embodiments within the scope of the technical features of the present application without departing from the technical features of the present application, and the changes or modifications still belong to the scope of the technical features of the present application.

Claims

1. A method for online correction of a radial stator sensor of a magnetic levitation molecular pump, the radial stator comprising, in order from top to bottom: The first radial protection bearing, the first radial displacement sensor, the XY magnetic bearing, the motor, the AB magnetic bearing, the second radial displacement sensor, and the second radial protection bearing; The XY magnetic bearing comprises an X+ magnetic pole pair, a Y+ magnetic pole pair, an X- magnetic pole pair, and a Y- magnetic pole pair; The AB magnetic bearing comprises an A+ magnetic pole pair, a B+ magnetic pole pair, an A- magnetic pole pair, and a B- magnetic pole pair; The first radial displacement sensor comprises an X+ sensor, a Y+ sensor, an X- sensor, and a Y- sensor; The second radial displacement sensor comprises an A+ sensor, a B+ sensor, an A- sensor, and a B- sensor; The method comprises the following steps: Step a: the spindle is placed at the positions of the first and second radial protection bearings, and the voltage values of each sensor are recorded when the spindle is at the positions of 0°, 45°, 90°, 135°, 180°, 225°, 270°, and 315°; The spindle at an arbitrary angle α is defined as follows: the center axis of the first radial protection bearing, the center axis of the spindle, and the projection of the spindle in the direction of movement of the X+ and A+ magnetic pole pairs are respectively denoted as G point, F point, and initial line, and the included angle between the initial line and the GF line in the counterclockwise direction is α; α is any value in 0°, 45°, 90°, 135°, 180°, 225°, 270°, and 315°; Step b: each sensor is calibrated: each sensor can obtain eight sets of voltage values and air gap length relationship data, and the voltage values and air gap length are fitted according to the linear relationship to realize the online calibration of each sensor.

2. The method of claim 1, wherein the method is characterized by: The inner surface diameters of the XY and AB magnetic bearings are respectively k1 and k2; the inner surface diameters of the first and second radial protection bearings are respectively n1 and n2; and the outer surface diameter of the spindle is m; When the spindle is at an arbitrary angle α position: The air gap length corresponding to the X+ sensor is: 0.5k1-0.5(n1-m)cosα-0.5(m 2 -((n1-m)sinα) 2 ) 0.5 ; The air gap length corresponding to the Y+ sensor is: 0.5k1-0.5(n1-m)cos(a+pi / 2)-0.5(m 2 -((n1-m)sin(a+pi / 2)) 2 ) 0.5 ; The air gap length corresponding to the X-sensor is: 0.5k1-0.5(n1-m)cos(a+π)-0.5(m 2 -((n1-m)sin(a+π)) 2 ) 0.5 ; The air gap length corresponding to the Y-sensor is: 0.5k1-0.5(n1-m)cos(a-pi / 2)-0.5(m 2 -((n1-m)sin(a-pi / 2)) 2 ) 0.5 ; The air gap length corresponding to the A+ sensor is: 0.5k2-0.5(n2-m)cosα-0.5(m 2 -((n2-m)sinα) 2 ) 0.5 ; The air gap length corresponding to the B+ sensor is: 0.5k2-0.5(n2-m)cos(a+π / 2)-0.5(m 2 -((n2-m)sin(a+π / 2)) 2 ) 0.5 ; The air gap length corresponding to the A-sensor is: 0.5k2-0.5(n2-m)cos(a+π)-0.5(m 2 -((n2-m)sin(a+π)) 2 ) 0.5 ; The air gap length corresponding to the B-sensor is: 0.5k2-0.5(n2-m)cos(a-p / 2)-0.5(m 2 -((n2-m)sin(a-p / 2)) 2 ) 0.5 .

3. The method of claim 2, wherein the method further comprises: Further comprising: step c, correcting the linear relationship; The voltage value-distance relationship of each sensor obtained in step b is expressed as: X+ sensor: y=k1x+d1; Y+ sensor: y=k2x+d2; X- sensor: y=k3x+d3; Y- sensor: y=k4x+d4; A+ sensor: y=k5x+d5; B+ sensor: y=k6x+d6; A- sensor: y=k7x+d7; B- sensor: y=k8x+d8; Firstly, the following eight coordinate points are used to fit a circle: ((k4Y-1+d4-k2Y+1-d2) / 2, (k3X-1+d3-k1X+1-d1) / 2); ((k4Y-2+d4-k2Y+2-d2) / 2, (k3X-2+d3-k1X+2-d1) / 2); ((k4Y-3+d4-k2Y+3-d2) / 2, (k3X-3+d3-k1X+3-d1) / 2); ((k4Y-4+d4-k2Y+4-d2) / 2, (k3X-4+d3-k1X+4-d1) / 2); ((k4Y-5+d4-k2Y+5-d2) / 2, (k3X-5+d3-k1X+5-d1) / 2); ((k4Y-6+d4-k2Y+6-d2) / 2, (k3X-6+d3-k1X+6-d1) / 2); ((k4Y-7+d4-k2Y+7-d2) / 2, (k3X-7+d3-k1X+7-d1) / 2); ((k4Y-8+d4-k2Y+8-d2) / 2, (k3X-8+d3-k1X+8-d1) / 2); The center coordinates of the circle can be expressed as: (△u, △v); Then, the linear relationship of the X+ sensor, the Y+ sensor, the X- sensor and the Y- sensor is corrected as follows: X+ sensor: y=k1x+d1+△v; Y+ sensor: y=k2x+d2+△u; X- sensor: y=k3x+d3-△v; Y- sensor: y=k4x+d4-△v; Secondly, a circle is fitted through the following eight points: ((k8B-1+d8-k6B+1-d6) / 2, (k7A-1+d7-k5A+1-d5) / 2); ((k8B-2+d8-k6B+2-d6) / 2, (k7A-2+d7-k5A+2-d5) / 2); ((k8B-3+d8-k6B+3-d6) / 2, (k7A-3+d7-k5A+3-d5) / 2); ((k8B-4+d8-k6B+4-d6) / 2, (k7A-4+d7-k5A+4-d5) / 2); ((k8B-5+d8-k6B+5-d6) / 2, (k7A-5+d7-k5A+5-d5) / 2); ((k8B-6+d8-k6B+6-d6) / 2, (k7A-6+d7-k5A+6-d5) / 2); ((k8B-7+d8-k6B+7-d6) / 2, (k7A-7+d7-k5A+7-d5) / 2); ((k8B-8+d8-k6B+8-d6) / 2, (k7A-8+d7-k5A+8-d5) / 2); The center coordinates of the circle can be expressed as: (△u’, △v’); Then, the linear relationship of the A+ sensor, the B+ sensor, the A- sensor and the B- sensor is corrected as follows: A+ sensor: y=k5x+d5+△v’; B+ sensor: y=k6x+d6+△u’; A- sensor: y=k7x+d7-△v’; B- sensor: y=k8x+d8-△u’.

4. A method for online correction of a radial stator sensor of a magnetic levitation molecular pump, the radial stator comprising, in order from top to bottom: The first radial protection bearing, the first radial displacement sensor, the XY magnetic bearing, the motor, the AB magnetic bearing, the second radial displacement sensor and the second radial protection bearing; The XY magnetic bearing comprises an X+ magnetic pole pair, a Y+ magnetic pole pair, an X- magnetic pole pair and a Y- magnetic pole pair; The AB magnetic bearing comprises an A+ magnetic pole pair, a B+ magnetic pole pair, an A- magnetic pole pair and a B- magnetic pole pair; The first radial displacement sensor comprises an X+ sensor, a Y+ sensor, an X- sensor and a Y- sensor; The second radial displacement sensor comprises an A+ sensor, a B+ sensor, an A- sensor and a B- sensor; Wherein, the inner surface diameter of XY, AB magnetic bearing is k1, k2 respectively; the inner surface diameter of the first, second radial protection bearing is n1, n2 respectively; the outer surface diameter of the main shaft is m; Phase angle: X+ direction is zero degree, the phase angle increases counterclockwise; It is characterized by comprising the following steps: S100, 0° phase angle detection: Only when the X+ direction magnetic pole pair and the A+ direction magnetic pole pair are energized, the main shaft is attached to the first and second radial protection bearing positions, and the voltage values of the X+ sensor, Y+ sensor, X- sensor, Y- sensor, A+ sensor, B+ sensor, A- sensor, and B- sensor at this time are recorded as X+1, Y+1, X-1, Y-1, A+1, B+1, A-1, and B-1 respectively. S200, 45° phase angle detection: only when the X+ direction magnetic pole pair, Y- direction magnetic pole pair, A+ direction magnetic pole pair, and B- direction magnetic pole pair are energized, the main shaft is attached to the first and second radial protection bearing positions, and the voltage values of the X+ sensor, Y+ sensor, X- sensor, Y- sensor, A+ sensor, B+ sensor, A- sensor, and B- sensor at this time are recorded as X+2, Y+2, X-2, Y-2, A+2, B+2, A-2, and B-2 respectively. S300, 90° phase angle detection: only when the Y- direction magnetic pole pair and the B- direction magnetic pole pair are energized, the main shaft is attached to the first and second radial protection bearing positions, and the voltage values of the X+ sensor, Y+ sensor, X- sensor, Y- sensor, A+ sensor, B+ sensor, A- sensor, and B- sensor at this time are recorded as X+3, Y+3, X-3, Y-3, A+3, B+3, A-3, and B-3 respectively. S400, 135° phase angle detection: only when the Y- direction magnetic pole pair, X- direction magnetic pole pair, B- direction magnetic pole pair, and A- direction magnetic pole pair are energized, the main shaft is attached to the first and second radial protection bearing positions, and the voltage values of the X+ sensor, Y+ sensor, X- sensor, Y- sensor, A+ sensor, B+ sensor, A- sensor, and B- sensor at this time are recorded as X+4, Y+4, X-4, Y-4, A+4, B+4, A-4, and B-4 respectively. S500, 180° phase angle detection: only when the X- direction magnetic pole pair and the A- direction magnetic pole pair are energized, the main shaft is attached to the first and second radial protection bearing positions, and the voltage values of the X+ sensor, Y+ sensor, X- sensor, Y- sensor, A+ sensor, B+ sensor, A- sensor, and B- sensor at this time are recorded as X+5, Y+5, X-5, Y-5, A+5, B+5, A-5, and B-5 respectively. S600, 225° phase angle detection: only when the X- direction magnetic pole pair, Y+ direction magnetic pole pair, A- direction magnetic pole pair, B+ direction magnetic pole pair are energized, the main shaft is attached to the first and second radial protection bearing positions, the voltage values of the X+ sensor, Y+ sensor, X- sensor, Y- sensor, A+ sensor, B+ sensor, A- sensor, B- sensor at this time are recorded, and are respectively recorded as X+6, Y+6, X-6, Y-6, A+6, B+6, A-6, B-6; S700, 270° phase angle detection: only when the Y+ direction magnetic pole pair, B+ direction magnetic pole pair are energized, the main shaft is attached to the first and second radial protection bearing positions, the voltage values of the X+ sensor, Y+ sensor, X- sensor, Y- sensor, A+ sensor, B+ sensor, A- sensor, B- sensor at this time are recorded, and are respectively recorded as X+7, Y+7, X-7, Y-7, A+7, B+7, A-7, B-7; S800, 315° phase angle detection: only when the Y+ direction magnetic pole pair, X+ direction magnetic pole pair, B+ direction magnetic pole pair, A+ direction magnetic pole pair are energized, the main shaft is attached to the first and second radial protection bearing positions, the voltage values of the X+ sensor, Y+ sensor, X- sensor, Y- sensor, A+ sensor, B+ sensor, A- sensor, B- sensor at this time are recorded, and are respectively recorded as X+8, Y+8, X-8, Y-8, A+8, B+8, A-8, B-8; S900, the voltage-distance relationship of the X+ sensor, Y+ sensor, X- sensor, Y- sensor, A+ sensor, B+ sensor, A- sensor, B- sensor is fitted according to a linear relationship respectively: y=kx+d, y represents the distance, x represents the voltage of the sensor, k is the slope, and d is the intercept; The 8 fitting point coordinates of the X+ sensor are: (X + 1, 0.5k1- 0.5(n1- m)cos0°- 0.5(m 2 -((n1- m)sin0°) 2 ) 0.5 ); (X + 2, 0.5k1- 0.5(n1- m)cos45°- 0.5(m 2 -((n1- m)sin45°) 2 ) 0.5 ) (X + 3, 0.5k1- 0.5(n1- m)cos90°- 0.5(m 2 -((n1- m)sin90°) 2 ) 0.5 ) (X + 4, 0.5k1- 0.5(n1- m)cos135°- 0.5(m 2 -((n1- m)sin135°) 2 ) 0.5 ) (X + 5, 0.5k1- 0.5(n1- m)cos180°- 0.5(m 2 -((n1- m)sin180°) 2 ) 0.5 ); (X + 6, 0.5k1- 0.5(n1- m)cos225°- 0.5(m 2 -((n1- m)sin225°) 2 ) 0.5 ) (X + 7, 0.5k1- 0.5(n1- m)cos270°- 0.5(m 2 -((n1- m)sin270°) 2 ) 0.5 ) (X + 8, 0.5k1- 0.5(n1- m)cos315°- 0.5(m 2 -((n1- m)sin315°) 2 ) 0.5 ) The 8 fitting point coordinates of the Y+ sensor are: (Y + 1, 0.5k1- 0.5(n1- m)cos90°- 0.5(m 2 -((n1- m)sin90°) 2 ) 0.5 ) (Y + 2, 0.5k1- 0.5(n1- m)cos135°- 0.5(m 2 -((n1- m)sin135°) 2 ) 0.5 ) (Y + 3, 0.5k1- 0.5(n1- m)cos180°- 0.5(m 2 - ((n1- m)sin180°) 2 ) 0.5 ); (Y + 4, 0.5k1- 0.5(n1- m)cos225°- 0.5(m 2 -((n1- m)sin225°) 2 ) 0.5 ) (Y + 5, 0.5k1- 0.5(n1- m)cos270°- 0.5(m 2 -((n1- m)sin270°) 2 ) 0.5 ) (Y + 6, 0.5k1- 0.5(n1- m)cos315°- 0.5(m 2 -((n1- m)sin315°) 2 ) 0.5 ) (Y + 7, 0.5k1- 0.5(n1- m)cos0°- 0.5(m 2 -((n1- m)sin0°) 2 ) 0.5 ) (Y + 8, 0.5k1- 0.5(n1- m)cos45°- 0.5(m 2 -((n1- m)sin45°) 2 ) 0.5 ) The 8 fitting point coordinates of the X- sensor are: (X - 1, 0.5k1- 0.5(n1- m)cos180°- 0.5(m 2 - ((n1- m)sin180°) 2 ) 0.5 ); (X - 2, 0.5k1- 0.5(n1- m)cos225°- 0.5(m 2 - ((n1- m)sin225°) 2 ) 0.5 ); (X - 3, 0.5k1- 0.5(n1- m)cos270°- 0.5(m 2 - ((n1- m)sin270°) 2 ) 0.5 ) (X - 4, 0.5k1- 0.5(n1- m)cos315°- 0.5(m 2 -((n1- m)sin315°) 2 ) 0.5 ) (X - 5, 0.5k1- 0.5(n1- m)cos0°- 0.5(m 2 - ((n1- m)sin0°) 2 ) 0.5 ); (X - 6, 0.5k1- 0.5(n1- m)cos45°- 0.5(m 2 - ((n1- m)sin45°) 2 ) 0.5 ) (X - 7, 0.5k1- 0.5(n1- m)cos90°- 0.5(m 2 - ((n1- m)sin90°) 2 ) 0.5 ); (X - 8, 0.5k1- 0.5(n1- m)cos135°- 0.5(m 2 - ((n1- m)sin135°) 2 ) 0.5 ) The 8 fitting point coordinates of the Y- sensor are: (Y - 1, 0.5k1- 0.5(n1- m)cos270°- 0.5(m 2 - ((n1- m)sin270°) 2 ) 0.5 ); (Y - 2, 0.5k1- 0.5(n1- m)cos315°- 0.5(m 2 - ((n1- m)sin315°) 2 ) 0.5 ) (Y - 3, 0.5k1- 0.5(n1- m)cos0°- 0.5(m 2 - ((n1- m)sin0°) 2 ) 0.5 ); (Y - 4, 0.5k1- 0.5(n1- m)cos45°- 0.5(m 2 - ((n1- m)sin45°) 2 ) 0.5 ) (Y - 5, 0.5k1- 0.5(n1- m)cos90°- 0.5(m 2 - ((n1- m)sin90°) 2 ) 0.5 ); (Y - 6, 0.5k1- 0.5(n1- m)cos135°- 0.5(m 2 - ((n1- m)sin135°) 2 ) 0.5 ) (Y - 7, 0.5k1- 0.5(n1- m)cos180°- 0.5(m 2 - ((n1- m)sin180°) 2 ) 0.5 ); (Y - 8, 0.5k1- 0.5(n1- m)cos225°- 0.5(m 2 - ((n1- m)sin225°) 2 ) 0.5 ) The 8 fitting point coordinates of the A+ sensor are: (A + 1, 0.5k2- 0.5(n2- m)cos0° - 0.5(m 2 - ((n2- m)sin0°) 2 ) 0.5 ); (A + 2, 0.5k2- 0.5(n2- m)cos45° - 0.5(m 2 - ((n2- m)sin45°) 2 ) 0.5 ) (A + 3, 0.5k2- 0.5(n2- m)cos90°- 0.5(m 2 - ((n2- m)sin90°) 2 ) 0.5 ); (A + 4, 0.5k2- 0.5(n2- m)cos135° - 0.5(m 2 - ((n2- m)sin135°) 2 ) 0.5 ) (A + 5, 0.5k2- 0.5(n2- m)cos180°- 0.5(m 2 - ((n2- m)sin180°) 2 ) 0.5 ); (A + 6, 0.5k2- 0.5(n2- m)cos225°- 0.5(m 2 -((n2- m)sin225°) 2 ) 0.5 ) (A + 7, 0.5k2- 0.5(n2- m)cos270° - 0.5(m 2 - ((n2- m)sin270°) 2 ) 0.5 ) (A + 8, 0.5k2- 0.5(n2- m)cos315° - 0.5(m 2 - ((n2- m)sin315°) 2 ) 0.5 ) The 8 fitting point coordinates of the B+ sensor are: (B + 1, 0.5k2- 0.5(n2- m)cos90° - 0.5(m 2 - ((n2- m)sin90°) 2 ) 0.5 ); (B + 2, 0.5k2- 0.5(n2- m)cos135° - 0.5(m 2 - ((n2- m)sin135°) 2 ) 0.5 ) (B + 3, 0.5k2- 0.5(n2- m)cos180°- 0.5(m 2 - ((n2- m)sin180°) 2 ) 0.5 ) (B + 4, 0.5k2- 0.5(n2- m)cos225°- 0.5(m 2 -((n2- m)sin225°) 2 ) 0.5 ) (B + 5, 0.5k2- 0.5(n2- m)cos270° - 0.5(m 2 - ((n2- m)sin270°) 2 ) 0.5 ); (B + 6, 0.5k2- 0.5(n2- m)cos315° - 0.5(m 2 - ((n2- m)sin315°) 2 ) 0.5 ) (B + 7, 0.5k2- 0.5(n2- m)cos0° - 0.5(m 2 - ((n2- m)sin0°) 2 ) 0.5 ) (B + 8, 0.5k2- 0.5(n2- m)cos45° - 0.5(m 2 - ((n2- m)sin45°) 2 ) 0.5 ) The 8 fitting point coordinates of the A- sensor are: (A-1, 0.5k2- 0.5(n2-m)cos180°- 0.5(m 2 -((n2-m)sin180°) 2 ) 0.5 ) (A-2, 0.5k2- 0.5(n2- m)cos225°- 0.5(m 2 -((n2- m)sin225°) 2 ) 0.5 ) (A-3, 0.5k2- 0.5(n2- m)cos270°- 0.5(m 2 - ((n2- m)sin270°) 2 ) 0.5 ) (A-4, 0.5k2- 0.5(n2-m)cos315°- 0.5(m 2 -((n2-m)sin315°) 2 ) 0.5 ) (A-5, 0.5k2- 0.5(n2- m)cos0°- 0.5(m 2 -((n2-m)sin0°) 2 ) 0.5 ) (A-6, 0.5k2- 0.5(n2- m)cos45°- 0.5(m 2 -((n2- m)sin45°) 2 ) 0.5 ) (A-7, 0.5k2-0.5(n2-m)cos90°-0.5(m 2 -((n2-m)sin90°) 2 ) 0.5 ) (A-8, 0.5k2- 0.5(n2-m)cos135°- 0.5(m 2 -((n2-m)sin135°) 2 ) 0.5 ) The 8 fitting point coordinates of the B- sensor are: (B-1, 0.5k2- 0.5(n2- m)cos270° - 0.5(m 2 - ((n2- m)sin270°) 2 ) 0.5 ); (B-2, 0.5k2- 0.5(n2- m)cos315° - 0.5(m 2 - ((n2- m)sin315°) 2 ) 0.5 ); (B-3, 0.5k2- 0.5(n2- m)cos0°- 0.5(m 2 - ((n2- m)sin0°) 2 ) 0.5 ) (B-4, 0.5k2- 0.5(n2- m)cos45°- 0.5(m 2 - ((n2- m)sin45°) 2 ) 0.5 ) (B-5, 0.5k2-0.5(n2-m)cos90°-0.5(m 2 -((n2-m)sin90°) 2 ) 0.5 ) (B-6, 0.5k2- 0.5(n2- m)cos135° - 0.5(m 2 - ((n2- m)sin135°) 2 ) 0.5 ) (B-7, 0.5k2-0.5(n2-m)cos180°-0.5(m 2 -((n2-m)sin180°) 2 ) 0.5 ) (B-8, 0.5k2- 0.5(n2-m)cos225°- 0.5(m 2 -((n2-m)sin225°) 2 ) 0.5 ).

5. The method of claim 4, wherein the method further comprises: determining a radial position of the rotor based on the measured magnetic field; and determining a radial position of the rotor based on the measured current. The currents of the coils of the 4 magnetic pole pairs in steps S200, S400, S600, and S800 remain the same.

6. The method of claim 4, wherein the method is characterized by: The currents of the X+ direction magnetic pole pair, Y- direction magnetic pole pair, A+ direction magnetic pole pair, and B- direction magnetic pole pair in S200 are the same.

7. The method of claim 4, wherein the method further comprises: determining a radial position of the rotor based on the measured magnetic field; and determining a radial position of the rotor based on the measured current. The currents of the Y- direction magnetic pole pair, X- direction magnetic pole pair, B- direction magnetic pole pair, and A- direction magnetic pole pair in S400 are the same.

8. The method of claim 4, wherein the method is characterized by: The currents of the X- direction magnetic pole pair, Y+ magnetic pole pair, A- direction magnetic pole pair, and B+ magnetic pole pair in S600 are the same.

9. The method of claim 4, wherein the method is characterized by: The currents of the Y+ magnetic pole pair, X+ magnetic pole pair, B+ magnetic pole pair, and A+ magnetic pole pair in S800 are the same.

10. The method of claim 4, wherein the method is a method of online correction of a radial stator sensor of a magnetic levitation molecular pump. Further comprising: S1000, correcting the linear relationship; The voltage value-distance relationship of each sensor is expressed as: X+ sensor: y=k1x+d1; Y+ sensor: y=k2x+d2; X- sensor: y=k3x+d3; Y- sensor: y=k4x+d4; A+ sensor: y=k5x+d5; B+ sensor: y=k6x+d6; A- sensor: y=k7x+d7; B- sensor: y=k8x+d8; First, the following 8 coordinate points are fitted to a circle: ((k4Y-1+d4-k2Y+1-d2) / 2, (k3X-1+d3-k1X+1-d1) / 2); ((k4Y-2+d4-k2Y+2-d2) / 2, (k3X-2+d3-k1X+2-d1) / 2); ((k4Y-3+d4-k2Y+3-d2) / 2, (k3X-3+d3-k1X+3-d1) / 2); ((k4Y-4+d4-k2Y+4-d2) / 2, (k3X-4+d3-k1X+4-d1) / 2); ((k4Y-5+d4-k2Y+5-d2) / 2, (k3X-5+d3-k1X+5-d1) / 2); ((k4Y-6+d4-k2Y+6-d2) / 2, (k3X-6+d3-k1X+6-d1) / 2); ((k4Y-7+d4-k2Y+7-d2) / 2, (k3X-7+d3-k1X+7-d1) / 2); ((k4Y-8+d4-k2Y+8-d2) / 2, (k3X-8+d3-k1X+8-d1) / 2); The center coordinates of the circle can be expressed as: (△u,△v); Then, the linear relationship of the X+ sensor, Y+ sensor, X- sensor, Y- sensor is corrected as: X+ sensor: y=k1x+d1+△v; Y+ sensor: y=k2x+d2+△u; X- sensor: y=k3x+d3-△v; Y- sensor: y=k4x+d4-△v; Second, the following 8 points are fitted to a circle: ((k8B-1+d8-k6B+1-d6) / 2, (k7A-1+d7-k5A+1-d5) / 2); ((k8B-2+d8-k6B+2-d6) / 2, (k7A-2+d7-k5A+2-d5) / 2); ((k8B-3+d8-k6B+3-d6) / 2, (k7A-3+d7-k5A+3-d5) / 2); ((k8B-4+d8-k6B+4-d6) / 2, (k7A-4+d7-k5A+4-d5) / 2); ((k8B-5+d8-k6B+5-d6) / 2, (k7A-5+d7-k5A+5-d5) / 2); ((k8B-6+d8-k6B+6-d6) / 2, (k7A-6+d7-k5A+6-d5) / 2); ((k8B-7+d8-k6B+7-d6) / 2, (k7A-7+d7-k5A+7-d5) / 2); ((k8B-8+d8-k6B+8-d6) / 2, (k7A-8+d7-k5A+8-d5) / 2); The center coordinates of the circle can be expressed as: (△u',△v'); Then, the linear relation correction of the A+ sensor, the B+ sensor, the A- sensor, and the B- sensor is: A+ sensor: y=k5x+d5+△v'; B+ sensor: y=k6x+d6+△u'; A- sensor: y=k7x+d7-△v'; B- sensor: y=k8x+d8-△u'.

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