A magnetic field adjusting method of a magnetic levitation planar motor

Abstract

The application belongs to the technical field of planar motor and provides a magnetic field adjusting method for magnetic suspension planar motor. The magnetic suspension planar motor comprises a mover assembly and a stator assembly. The mover assembly comprises a mover top plate, a controller cabin, an adjustable magnetic array layer and a mover bottom plate connected from top to bottom. The adjustable magnetic array layer comprises a permanent magnet array and a magnetic field reconstruction unit. The permanent magnet array is composed of multiple permanent magnet subarray units. The magnetic field reconstruction unit is arranged in the magnetic pole gap of the permanent magnet array. Each magnetic field reconstruction unit comprises a micro soft magnetic core and a micro coil wound on the micro soft magnetic core. The controller cabin is provided with a mover controller for receiving instructions and controlling the current of the micro coil. The method is adjusted by controlling the magnetic field reconstruction unit. The application solves the problem of poor utilization of magnetic leakage field caused by the physical gap between the mover permanent magnets in the planar motor.

Description

TECHNICAL FIELD

[0001] The present application is suitable for the technical field of planar motor, and particularly relates to a magnetic field adjusting method of a magnetic levitation planar motor. BACKGROUND

[0002] As a kind of driving device that can realize the non-contact, high-precision and high-speed movement of the mover in two-dimensional or three-dimensional space, the magnetic levitation planar motor has important application prospects in the fields of semiconductor lithography, precision manufacturing and micro-nano operation. Its working principle usually relies on the electromagnetic interaction between the permanent magnet array on the mover and the coil array on the stator to generate the required levitation force and driving force. In a typical magnetic levitation planar motor, the mover assembly is provided with a magnetic array composed of permanent magnets (such as a Halbach array), which utilizes the interaction between the magnetic field generated by the permanent magnets and the electromagnetic coils on the stator side to achieve levitation and driving.

[0003] However, the mover structure in the prior art generally has the problem of low magnetic field utilization rate, which seriously restricts the thrust density and energy efficiency ratio of the motor. Specifically, the permanent magnet array on the existing mover has certain physical gaps, which cause significant magnetic flux leakage. The gap area between the permanent magnets cannot be effectively constrained and guided like inside the magnets, but instead diverges to the surrounding space, forming a closed loop, rather than all concentrating in the working air gap. The leakage of magnetic flux causes the magnetic field distribution to be more uneven on the working surface of the mover, and the magnetic field density at the gap between the magnetic poles is significantly lower than the ideal value. SUMMARY

[0004] The present application provides a mover assembly, a magnetic levitation planar motor and a magnetic field adjusting method, aiming to solve the problem of low magnetic field utilization rate caused by the physical gaps between the permanent magnets of the mover in the planar motor, and the technical solution is as follows:

[0005] A magnetic field adjusting method of a magnetic levitation planar motor, the magnetic levitation planar motor comprising a mover assembly and a stator assembly, the mover assembly comprising a mover top plate, a controller cabin, an adjustable magnetic array layer and a mover bottom plate connected from top to bottom; the adjustable magnetic array layer comprising a permanent magnet array and a magnetic field reconstruction unit, the permanent magnet array being composed of a plurality of permanent magnet sub-array units; the magnetic field reconstruction unit being arranged in the magnetic pole gap of the permanent magnet array, each magnetic field reconstruction unit comprising a micro soft magnetic core and a micro coil wound on the micro soft magnetic core; the controller cabin being provided with a mover controller for receiving instructions and controlling the current of the micro coil; the magnetic pole gap being the gap between adjacent permanent magnets or the unit gap between adjacent permanent magnet sub-array units in the permanent magnet sub-array unit;

[0006] The method adjusts by controlling the magnetic field reconstruction unit, comprising the following steps:

[0007] S1: obtaining adjustment parameters of a magnetic field reconstruction unit to be adjusted based on the magnetic field distribution data of the moving object, the magnetic field distribution data including actual magnetic field distribution data and target magnetic field distribution data, the adjustment parameters of the magnetic field reconstruction unit including the number, the magnetic field strength and the magnetic field direction of the magnetic field reconstruction unit;

[0008] S2: obtaining the current parameters of the corresponding magnetic field reconstruction unit through the magnetic field strength-current mapping table based on the adjustment parameters of the magnetic field reconstruction unit;

[0009] S3: driving the magnetic field reconstruction unit to generate an additional magnetic field based on the current parameters in the step S2.

[0010] On the basis of the above technical solution, the magnetic pole gap is the gap between adjacent permanent magnets in the permanent magnet subarray unit.

[0011] On the basis of the above technical solution, the method for obtaining the current parameters of the magnetic field reconstruction unit in the step S2 includes the following steps:

[0012] S21: calling the magnetic field strength-current mapping table of the magnetic field reconstruction unit;

[0013] S22: if the magnetic field strength of the magnetic field reconstruction unit is a non-discrete value, calculating the corresponding current through linear interpolation based on two adjacent discrete values in the current mapping table of the magnetic field reconstruction unit; if the magnetic field strength of the magnetic field reconstruction unit is a discrete value, directly reading the corresponding current.

[0014] In another aspect, the method includes the following steps:

[0015] A1: obtaining the real-time magnetic field strength B after through the Hall sensor array of the stator assembly; after ;

[0016] A2: calculating the magnetic field compensation amount ΔB'=B before -B after according to the real-time magnetic field strength B after and the initial magnetic field strength B before ;

[0017] A3: judging whether compensation is needed according to the magnetic field compensation amount ΔB' and the compensation threshold Bq;

[0018] A4: if the magnetic field strength needs compensation, obtaining the current parameters of the corresponding magnetic field reconstruction unit through the magnetic field strength-current mapping table based on the adjustment parameters of the magnetic field reconstruction unit;

[0019] A5: driving the magnetic field reconstruction unit to generate an additional magnetic field based on the current parameters obtained in the step A4.

[0020] On the basis of the above scheme, the method for acquiring the real-time magnetic field intensity through the Hall sensor array is:

[0021] A11: acquiring the real-time voltage value Vh output by the Hall sensor array;

[0022] A12: converting the real-time voltage value into the real-time magnetic field intensity B through the calibration coefficient K after =K×Vh.

[0023] Further, the mover assembly further comprises a reinforcement layer, which is arranged between the adjustable magnetic array layer and the mover bottom plate; the reinforcement layer comprises a reinforcement coil array, the projection position of the reinforcement coil on the plane corresponds to the position of the permanent magnet array, and the method further comprises:

[0024] A6: if the micro coil current of the magnetic field reconstruction unit is Imax, and at this time B after +ΔB'<B before , starting the compensation of the reinforcement layer;

[0025] A7: passing the compensation current into the reinforcement coil of the reinforcement layer, and the magnetic field generated by the compensation current is in the same direction as the magnetization direction of the corresponding permanent magnet.

[0026] On the basis of the above scheme, the compensation current calculation method is:

[0027] A71: calculating the average magnetic field deviation ΔBavg of the real-time magnetic field intensity B after +ΔB' after compensation by the magnetic field reconstruction unit and the initial magnetic field intensity B before .

[0028] A72: obtaining the reinforcement layer compensation current Ie=ΔBavg / Ke, and Ke is the current-magnetic field conversion coefficient.

[0029] Advantages

[0030] Compared with the prior art, the advantages of the present application are:

[0031] 1. The present application integrates the magnetic field reconstruction unit at the magnetic pole gap of the permanent magnet array, generates an additional magnetic field in the same direction as the bias magnetic field, effectively compensates for the magnetic flux leakage caused by the physical gap, and greatly improves the effective utilization rate of the magnetic field and the thrust output capacity per unit volume / mass.

[0032] 2. The present application compensates for the magnetic decay of the permanent magnet through the magnetic field reconstruction unit or the reinforcement layer, overcomes the performance decline defects of the traditional planar motor caused by factors such as aging or temperature drift of the permanent magnet, ensures the stability of the long-term operation of the planar motor system, and significantly prolongs the service life of the mover assembly. BRIEF DESCRIPTION OF DRAWINGS

[0033] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only one embodiment of the present invention. For those skilled in the art, other embodiments can be derived from the provided drawings without creative effort.

[0034] Figure 1 : A schematic diagram of the structure of the magnetic levitation planar motor described in this invention;

[0035] Figure 2 : Figure 1 An explosion diagram;

[0036] Figure 3 : A schematic diagram of the existing Hellbeck array structure;

[0037] Figure 4 : A schematic diagram showing the location of the magnetic field reconstruction unit in the gap between adjacent permanent magnets in the Heilbeck array described in this invention;

[0038] Figure 5 : A schematic diagram of the magnetization of the magnetic field reconstruction unit of the gap between adjacent permanent magnets in the Heilbeck array of the present invention;

[0039] Figure 6 : A schematic diagram of the structure after splicing existing permanent magnet subarray units;

[0040] Figure 7 : A schematic diagram of the magnetic field reconstruction unit position of the inter-unit gap between the permanent magnet sub-array units described in this invention;

[0041] Figure 8 : A schematic diagram of the magnetic field reconstruction unit for the gap between permanent magnet subarray units described in this invention. Detailed Implementation

[0042] The present invention will be further described below with reference to the accompanying drawings and examples:

[0043] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0044] In the description of the present application, it should be noted that unless otherwise explicitly specified and limited, the terms "mounting", "connection", "connecting" should be understood in a broad sense, for example, it can be fixed connection, or detachable connection, or integrally connected; it can be directly connected, or indirectly connected through an intermediate medium. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0045] In the description of the present application, it should be understood that the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application.

[0046] Embodiment 1

[0047] The present embodiment provides a mover assembly, which comprises a mover top plate 1, a controller cabin 2, an adjustable magnetic array layer 3 and a mover bottom plate 4 connected from top to bottom.

[0048] The adjustable magnetic array layer 3 comprises a permanent magnet array and a magnetic field reconstruction unit 32, which is arranged by a plurality of permanent magnet subarray units; the magnetic field reconstruction unit 32 is arranged in the magnetic pole gap of the permanent magnet array, and each magnetic field reconstruction unit 32 comprises a micro soft magnetic core and a micro coil wound on the micro soft magnetic core.

[0049] The soft magnetic core can be an elongated column, and the size of the magnetic field reconstruction unit substantially matches the magnetic pole gap of the permanent magnet array. The micro coil is continuously wound along the axis of the soft magnetic core to form a compact coil column.

[0050] In order to reduce heat generation, the micro soft magnetic core is made of amorphous or nanocrystalline material with low loss and high saturation magnetic induction intensity to reduce the core loss. The coil uses high-temperature resistant enameled wire.

[0051] The mover assembly further comprises a reinforcing layer arranged between the adjustable magnetic array layer 3 and the mover bottom plate 4; the reinforcing layer comprises a reinforcing coil, and the projection position of the reinforcing coil on the plane corresponds to the position of the permanent magnet array.

[0052] The controller cabin 2 is provided with a mover controller for receiving instructions and controlling the current of the micro coil. The micro coil leads converge and are connected to the drive circuit in the controller cabin 2 through a flexible circuit. When the micro coil is connected to the current, an additional magnetic field is formed at the magnetic pole gap. The additional magnetic field and the bias magnetic field generated by the permanent magnet array at the magnetic pole gap are vector superimposed, thereby enhancing the magnetic field strength of the magnetic pole gap region.

[0053] Figure 6 It is a schematic diagram of an existing permanent magnet unit in a Halbach array. A plurality of such permanent magnet array units form the entire mover permanent magnet array. The magnetization direction of each permanent magnet is shown by the arrow, forming a basic magnetic field distribution.

[0054] The two-dimensional Halbach array 31 includes a first magnet arranged at the center and four second magnets arranged around the first magnet. The magnetic field direction of the first magnet is arranged outward perpendicular to the fixed surface, and the magnetic field direction of the four second magnets arranged around the first magnet points horizontally to the first magnet. The Halbach array has a bias magnetic field with a specific direction and strength formed by the joint action of adjacent permanent magnets at the magnetic pole gap.

[0055] The magnetic field reconstruction unit can be arranged in the magnetic pole gap between the four magnets arranged around the first magnet and the first magnet.

[0056] As shown in Figure 4 There is a magnetic pole gap between adjacent permanent magnets, and a magnetic field reconstruction unit 32 is embedded in each gap. The magnetic field reconstruction unit 32 is composed of a micro soft magnetic core and a micro coil wound thereon.

[0057] When the mover controller needs to adjust the local magnetic field according to the instructions, it will pass a precisely controlled current to the micro coil at a specific location. The current flowing through the micro coil will generate a controllable additional magnetic field, and the direction and strength of the additional magnetic field depend on the direction and size of the coil current. The additional magnetic field and the bias magnetic field formed by the surrounding permanent magnets at the gap are vector superimposed.

[0058] As shown in Figure 5 By controlling the current direction, the additional magnetic field and the bias magnetic field are in the same direction, thereby realizing the magnetic field strength of the local area.

[0059] In a static state (no current through the micro coil), the soft magnetic core of the magnetic field reconstruction unit 32 has extremely high magnetic permeability, forming a low-magnetic-resistance path to guide a part of the originally leaked magnetic force lines through the soft magnetic core. This will change the static magnetic field distribution of the entire array, but the main static magnetic field is still dominated by the permanent magnet array.

[0060] Adjustment time (current through the micro coil): when the micro coil of the magnetic field reconstruction unit 32 is electrified, an additional magnetic field is formed at the magnetic pole gap, which can be the same as the direction of the bias magnetic field of the permanent magnet array, enhancing the effect of the local magnetic field.

[0061] By embedding the micro magnetic field reconstruction unit 32 in the existing magnetic pole gap, the overall thickness or volume of the rotor is not increased, the compactness of the rotor is maximized, high acceleration and high dynamic response are achieved, and the adverse effects on the motor air gap are avoided.

[0062] The permanent magnet array and the magnetic field reconstruction unit 32 are fixed as a whole module by high-strength heat-conducting epoxy resin. The high-strength epoxy resin can firmly bond and fix the multiple permanent magnets and the embedded micro magnetic field reconstruction unit 32 together to form a rigid whole. During high-speed and high-acceleration movement of the rotor, the permanent magnets will not loosen or the reconstruction unit 32 will not fall off due to severe vibration or impact, ensuring the structural integrity and long-term reliability of the rotor assembly

[0063] The controller cabin 2 also integrates a wireless communication module, a wireless power supply module and a micro drive circuit; the wireless communication module and the micro drive circuit are electrically connected with the rotor controller; the micro drive circuit is also electrically connected with the micro coil of the magnetic field reconstruction unit 32.

[0064] The wireless power supply module provides power for the rotor controller, the micro drive circuit and the micro coil, and the wireless communication module receives external instructions and returns status information, so that the rotor can move freely, quickly and unrestrictedly.

[0065] Embodiment 2

[0066] Based on the above embodiment 1, the difference between the rotor assembly provided in this embodiment and embodiment 1 is that the permanent magnet array is composed of multiple independent permanent magnet sub-array units, and the magnetic pole gap of the magnetic field reconstruction unit is the inter-unit gap between the permanent magnet sub-array units. In other embodiments, the magnetic field reconstruction unit is arranged in the inter-unit gap between the permanent magnet sub-array units and the gap between the adjacent permanent magnets in the unit.

[0067] Reference Figure 6 The permanent magnet array of the rotor is composed of multiple independent permanent magnet sub-array units. Each sub-array unit is a small two-dimensional Halbach array (or other optimized magnetic circuit permanent magnet combination) with strong local magnetic field focusing capability. These permanent magnet sub-array units are spliced together according to the predetermined two-dimensional layout on the rotor bottom plate to form a complete magnetic array layer.

[0068] When splicing, a relatively wide inter-unit gap will be formed between adjacent permanent magnet sub-array units. These gaps are no longer tiny gaps between individual permanent magnets, but rather regions with a certain width between permanent magnet sub-array units. The magnetic field reconstruction units 32 are arranged in these inter-unit gaps. Similar to embodiment 1, multiple reconstruction units 32 are distributed along the gap.

[0069] When the mover controller needs to be regulated, the micro drive circuit applies a specific current to the micro coil in the inter-unit gap according to the instructions of the mover controller. The current generates an additional magnetic field in the micro soft magnetic core. This additional magnetic field will vectorially superimpose with the edge magnetic field generated by the two adjacent permanent magnet sub-array units at the boundary. By controlling the current of each reconstruction unit in the gap, the magnetic field coupling strength between adjacent sub-array units can be enhanced. For example, the enhanced magnetic field can connect two sub-arrays, making the overall magnetic field more continuous.

[0070] Further, the magnetization direction of the magnetic field reconstruction unit 32 is diagonal to the magnetic block. According to the magnetization direction of the surrounding magnetic blocks, the diagonal magnetization direction is set to achieve the same direction of the superimposed magnetic field. The magnetic circuit direction is better aligned with the bias magnetic field direction at the gap, which can enhance the coupling efficiency of the additional magnetic field and the bias magnetic field.

[0071] Specifically, as shown in Figure 7 and Figure 8 This embodiment shows a permanent magnet array composed of two permanent magnet sub-array units (two-dimensional Halbach array) as an example for illustration. There is a first central magnet with a magnetization direction outward (indicated by a dot) and a second central magnet with a magnetization direction inward (indicated by a cross). A magnet pointing to the first central magnet is arranged horizontally to the first central magnet, and a magnet pointing to the first central magnet is arranged vertically to the first central magnet. Magnets opposite to the magnetic field of the second central magnet are arranged horizontally and vertically to the second central magnet.

[0072] A plurality of reconstruction units 32 are added in the gap between the two permanent magnet sub-array units. The reconstruction units 32 in the corner gap on the side of the first central magnet point to the first central magnet, and the reconstruction units 32 in the corner gap on the side of the second central magnet are opposite to the magnetic field of the second central magnet. Further, the magnetization direction of the magnetic field reconstruction unit 32 arranged in the corner is diagonal to the magnetic block. In order to better align the magnetic circuit direction with the bias magnetic field direction at the gap, the coupling efficiency of the additional magnetic field and the bias magnetic field can be enhanced. At this time, the magnetic field direction of the reconstruction unit 32 between the first central magnet and the second central magnet is downward.

[0073] Embodiment 3

[0074] As shown in Figure 1 and Figure 2As shown, the embodiment provides a magnetic levitation planar motor which is configured with the mover assembly 10 of any one of embodiments 1 and 2.

[0075] The magnetic levitation planar motor further comprises a stator assembly 11, which comprises a stator top plate 5, a coil array layer 6 and a stator base 8 arranged from top to bottom; the coil array layer 6 generates electromagnetic force after being supplied with current, and interacts with the magnetic field generated by the adjustable magnetic array layer 3 of the mover assembly 10 to drive the mover assembly 10 to levitate and move above the stator assembly.

[0076] The coil array layer 6 is a direct source of electromagnetic force, and interacts with the magnetic field of the adjustable magnetic array layer 3 after being supplied with current to generate precisely controllable Lorentz force or magnetic resistance force, thereby realizing full freedom of levitation of the mover in X, Y and Z directions and high-speed and high-precision movement in a two-dimensional plane, and meeting the core requirements of a precision positioning system.

[0077] The stator top plate 5 is made of high-permeability material (such as silicon steel sheet), which can effectively guide and converge the magnetic flux generated by the coil array, reduce magnetic leakage, and form a more efficient closed magnetic circuit.

[0078] The stator assembly 11 further comprises a sensor layer 7 for detecting position information or magnetic field data of the mover assembly 10, the sensor layer 7 being arranged between the coil array layer 6 and the stator base 8, and the sensors on the sensor layer 7 can be Hall sensors or eddy current sensors.

[0079] Embodiment 4

[0080] The embodiment provides a magnetic field adjustment method applied to the magnetic levitation planar motor of embodiment 3, and the method comprises the following steps:

[0081] S1: obtaining adjustment parameters of a magnetic field reconstruction unit to be adjusted based on magnetic field distribution data of a mover, the magnetic field distribution data comprising actual magnetic field distribution data and target magnetic field distribution data, and the adjustment parameters of the magnetic field reconstruction unit comprising a number, a magnetic field strength and a magnetic field direction of the magnetic field reconstruction unit;

[0082] In the embodiment, the step S1 of obtaining the adjustment parameters of the magnetic field reconstruction unit specifically comprises:

[0083] S11: judging whether the magnetic field at the pole gap needs to be adjusted according to the actual magnetic field distribution data and the target magnetic field distribution data, the magnetic field distribution data comprising a magnetic field strength and a magnetic field direction:

[0084] (1) obtaining a magnetic field strength Ba, a magnetic field direction θa at the pole gap, a target magnetic field strength Bb and a magnetic field direction θb at the pole gap;

[0085] (2) If Bb-Ba>0, the magnetic field at the pole gap needs to be enhanced, and the direction of the enhanced magnetic field is the same as θa; if Bb-Ba<0, the magnetic field at the pole gap needs to be weakened, and the direction of the enhanced magnetic field is opposite to θa.

[0086] S12: Obtain the adjustment parameters of the magnetic field reconstruction unit corresponding to the pole gap according to Ba, Bb and the type of the pole gap, specifically including the number, the magnetic field strength ΔB and the magnetic field direction θ.

[0087] In this embodiment, the magnetic field distribution data of the mover includes actual magnetic field distribution data and target magnetic field distribution data. The actual magnetic field distribution data is obtained by acquiring the pre-measured and stored mover magnetic field strength data or by acquiring the real-time measured mover magnetic field strength data. The target magnetic field distribution data is the magnetic field distribution data designed by experiment to meet the predetermined electromagnetic force of the mover.

[0088] S2: Based on the adjustment parameters of the magnetic field reconstruction unit, obtain the current parameters of the corresponding magnetic field reconstruction unit through the magnetic field strength-current mapping table, the current parameters including the size and direction of the current;

[0089] In this embodiment, the step S2 of obtaining the current parameters of the magnetic field reconstruction unit specifically includes:

[0090] S21: Call the pre-stored magnetic field strength-current mapping table of the magnetic field reconstruction unit, and the magnetic field strength-current mapping table corresponds the current parameters of each magnetic field reconstruction unit;

[0091] S22: If the magnetic field strength is a non-discrete value, calculate the corresponding current through linear interpolation based on two adjacent discrete values in the magnetic field strength-current mapping table; if the magnetic field strength is a discrete value, directly read the corresponding current parameters to obtain the size and direction of the current.

[0092] S3: Based on the size and direction of the current obtained in the step S2, drive the magnetic field reconstruction unit to generate an additional magnetic field;

[0093] The S3 of this embodiment specifically includes the following steps:

[0094] S31: Convert the size and direction of the current into a PWM control signal, send the PWM control signal to a micro drive circuit, and output the current from the micro drive circuit;

[0095] S32: Input the current output from the micro drive circuit into the micro coil of the corresponding magnetic field reconstruction unit.

[0096] The above steps of the embodiment control the current of the micro coil accurately, so that the magnetic field reconstruction unit generates an additional magnetic field in the magnetic pole gap, the additional magnetic field is vector superimposed with the bias magnetic field or the actual magnetic field of the permanent magnet array, and adjustment of the local magnetic field is realized.

[0097] The embodiment controls the additional magnetic field of different magnetic field reconstruction units, selectively changes the additional magnetic field of one or more magnetic field reconstruction units according to actual needs, and effectively compensates for the magnetic flux leakage caused by the physical gap.

[0098] Embodiment 5

[0099] The embodiment provides a magnetic field adjustment method of a magnetic levitation planar motor, and aims to solve the problem of magnetic field attenuation caused by aging of permanent magnets in a mover of an existing magnetic levitation planar motor. The stator assembly 11 includes a sensor layer 7 arranged between the coil array layer 6 and the stator base 8, and the sensor layer 7 is a Hall sensor array. Since the influence of permanent magnet aging on the magnetic pole gap is large, the embodiment compensates by adjusting the magnetic field strength of the magnetic pole gap, and specifically includes the following steps:

[0100] A1: Obtain real-time magnetic field strength B through the Hall sensor array of the stator assembly after ;

[0101] In the embodiment, the step A1 specifically includes:

[0102] A11: Obtain real-time voltage value Vh output by the Hall sensor array;

[0103] A12: Convert the real-time voltage value into real-time magnetic field strength B after =K×Vh through a calibration coefficient K, the calibration coefficient K is a conversion coefficient of the Hall sensor for converting a voltage signal into a magnetic field strength, and the unit is mT / V.

[0104] A2: Calculate a magnetic field compensation amount ΔB'=B after -B before according to the real-time magnetic field strength B before and an initial magnetic field strength B after ;

[0105] In the embodiment, the method for obtaining the initial magnetic field strength in the step A2 specifically includes:

[0106] A21: Obtain an initial voltage value Vi output by the Hall sensor when the mover is factory-finished or in a non-aging state of the permanent magnet;

[0107] A22: Calculate the initial magnetic field strength B before =K×Vi through the calibration coefficient K;

[0108] A23: store the initial magnetic field strength into the Flash memory.

[0109] A3: determine whether compensation is needed according to the magnetic field compensation amount ΔB' and a compensation threshold Bq: if ΔB'>Bq, compensation of the magnetic field strength is needed; if ΔB'<Bq, compensation of the magnetic field strength is not needed.

[0110] A4: if the magnetic field strength needs compensation, based on the adjustment parameter of the magnetic field reconstruction unit, obtain the corresponding current parameter of the magnetic field reconstruction unit through a magnetic field strength-current mapping table, the current parameter including the size and direction of the current.

[0111] In the embodiment, the step A4 further includes positioning the magnetic field reconstruction unit that needs compensation of the magnetic field strength, and specifically includes:

[0112] A41: obtain the real-time position (Xm, Ym) of the mover and the position (Xs, Ys) of the magnetic field to be compensated.

[0113] The real-time position of the mover in the embodiment is obtained by the existing method such as the stator-side grating ruler or camera described in the prior art, and the coordinate of the real-time position of the mover is the real-time position coordinate of the center point of the mover in the stator coordinate system.

[0114] The position of the magnetic field to be compensated in the embodiment is the position of the magnetic field strength to be compensated detected by the Hall sensor, and the position corresponds to the position of the Hall sensor in the stator coordinate system.

[0115] A42: calculate the offset of the magnetic field reconstruction unit to be compensated to the center point of the mover (i.e. the real-time position of the mover).

[0116] In the embodiment, the position (Xs, Ys) of the magnetic field to be compensated corresponds to the position of the magnetic field reconstruction unit on the mover. Since they are in a projection relationship, the coordinates in x and y directions are the same except for the z coordinate, and therefore, when the position of the magnetic field to be compensated on the stator is positioned by the Hall sensor, the position of the magnetic field reconstruction unit to be adjusted in the stator coordinate system can be correspondingly determined as (Xs, Ys).

[0117] According to the real-time position (Xm, Ym) of the mover, the offset (ΔX, ΔY) of the magnetic field reconstruction unit to be adjusted to the center point of the mover is calculated, ΔX=Xs-Xm and ΔY=Ys-Ym, which is convenient for subsequent calculation and determination of the positioning of the magnetic field reconstruction unit to be adjusted on the mover.

[0118] A43: Positioning the magnetic field reconstruction unit to be adjusted: The position of the magnetic field reconstruction unit in the mover is fixed, so taking the center point of the mover as the coordinate origin, the position (Xv, Yv) of each magnetic field reconstruction unit in the mover coordinate system is obtained, and the position (Xv, Yv) of each magnetic field reconstruction unit in the mover coordinate system is matched with the offset (ΔX, ΔY) of the magnetic field reconstruction unit to the center point of the mover to position the magnetic field reconstruction unit to be adjusted. The positioning of the magnetic field reconstruction unit to be adjusted can be the position or number of the magnetic field reconstruction unit to be adjusted.

[0119] A5: Based on the current size and direction obtained in step A4, drive the magnetic field reconstruction unit at the corresponding position to generate an additional magnetic field.

[0120] In this embodiment, the step of driving the magnetic field reconstruction unit to generate an additional magnetic field in A5 is the same as that in embodiment 4, and will not be repeated here.

[0121] In this embodiment, the air gap magnetic field is directly detected by the Hall sensor, and the air gap magnetic field is compared with the unaged air gap magnetic field. The position to be compensated is matched with the magnetic field reconstruction unit in the mover magnetic pole gap, and the magnetic field is compensated to a certain extent by the additional magnetic field of the magnetic field reconstruction unit to ensure the real-time compensation of the magnetic field during operation. At the same time, the above adjustment method improves the response speed and improves the control accuracy during real-time movement of the mover.

[0122] Embodiment 6

[0123] The embodiment provides a magnetic field adjustment method of a magnetic suspension planar motor, which is the same as that in embodiment 5, except that the magnetic field is compensated by the reinforcing layer in the mover assembly in embodiment 1, aiming to solve the problem that the magnetic field is aged to the extent that it is difficult to achieve effective compensation by the magnetic field reconstruction unit 32. The method comprises:

[0124] A6: If the micro coil current of the magnetic field reconstruction unit is Imax, and at this time B after +ΔB'<B before , start the compensation of the reinforcing layer;

[0125] A7: A compensation current is passed through the reinforcing coil of the reinforcing layer, and the magnetic field generated by the compensation current has the same direction as the magnetization direction of the corresponding permanent magnet;

[0126] In step A7 of the embodiment, the compensation current calculation method is:

[0127] A71: Calculate the average magnetic field deviation ΔBavg of the real-time magnetic field strength B after +ΔB' after compensation by the magnetic field reconstruction unit and the initial magnetic field strength B before .

[0128] A72: obtain an enhanced layer compensation current Ie = ΔBavg / Ke, Ke is a current-magnetic field conversion coefficient, which is determined by the number of turns, size, etc.

[0129] The embodiment is used to solve the problem that the additional magnetic field generated by the magnetic field reconstruction unit cannot compensate for the aging of the permanent magnet, and effectively compensates for the attenuation of the magnetic field generated by the permanent magnet by controlling the enhanced coil of the enhanced layer to generate a magnetic field.

[0130] It should be noted that the mover controller, wireless communication module, wireless power supply module, micro drive circuit, and sensor layer of the embodiment are all general standard components or components known to those skilled in the art, and their structures and principles can be known by those skilled in the art through technical manuals or through conventional experimental methods.

[0131] The above describes the present application by way of example, but the present application is not limited to the above specific embodiments, and any modification or change made based on the present application falls within the scope of the present application.

Claims

1. A method for magnetic field adjustment of a magnetic levitation planar motor comprising a mover assembly (10) and a stator assembly (11), characterized in that, The mover assembly (10) comprises a mover top plate (1), a controller cabin (2), an adjustable magnetic array layer (3) and a mover bottom plate (4) connected from top to bottom; the adjustable magnetic array layer (3) comprises a permanent magnet array and a magnetic field reconstruction unit (32), the permanent magnet array is composed of a plurality of permanent magnet subarray units; the magnetic field reconstruction unit (32) is arranged in the magnetic pole gap of the permanent magnet array, each magnetic field reconstruction unit (32) comprises a micro soft magnetic core and a micro coil wound on the micro soft magnetic core; the controller cabin (2) is provided with a mover controller for receiving instructions and controlling the current of the micro coil; the magnetic pole gap is the gap between adjacent permanent magnets in the permanent magnet subarray unit or the unit gap between adjacent permanent magnet subarray units, and the permanent magnet subarray unit adopts a two-dimensional Halbach array; The method adjusts the magnetic field of the mover assembly by controlling the magnetic field reconstruction unit (32), comprising the following steps: S1: based on the magnetic field distribution data of the mover assembly, obtaining the adjustment parameters of the magnetic field reconstruction unit (32) that needs to be adjusted, the magnetic field distribution data includes real-time magnetic field distribution data and initial magnetic field distribution data, and the adjustment parameters of the magnetic field reconstruction unit (32) include the number of magnetic field reconstruction units, magnetic field strength and magnetic field direction; According to the real-time magnetic field strength and the initial magnetic field strength, the magnetic field compensation amount is calculated, and the initial magnetic field strength is the magnetic field strength detected by the Hall sensor when the mover assembly is shipped or in the non-aging state of the permanent magnet; According to the magnetic field compensation amount and the compensation threshold, it is judged whether compensation is needed; S2: if the magnetic field strength needs to be compensated, based on the adjustment parameters of the magnetic field reconstruction unit (32), the current parameters of the corresponding magnetic field reconstruction unit (32) are obtained through the magnetic field strength-current mapping table; S3: based on the current parameters in step S2, the magnetic field reconstruction unit (32) generates an additional magnetic field.

2. The magnetic field adjustment method of a magnetic levitation planar motor according to claim 1, characterized by, The method for obtaining the current parameters of the magnetic field reconstruction unit in step S2 comprises the following steps: S21: call the magnetic field strength-current mapping table of the magnetic field reconstruction unit (32); S22: if the magnetic field strength of the magnetic field reconstruction unit (32) is a non-discrete value, the corresponding current is calculated by linear interpolation based on two adjacent discrete values in the current mapping table of the magnetic field reconstruction unit (32); if the magnetic field strength of the magnetic field reconstruction unit (32) is a discrete value, the corresponding current is directly read.

3. The magnetic field adjustment method of a magnetic levitation planar motor according to claim 1, characterized by, The stator assembly (11) comprises a sensor layer (7), which is arranged between the coil array layer (6) and the stator base (8), and the sensor layer (7) is a Hall sensor array; The method for obtaining the real-time magnetic field strength through the Hall sensor array is: Obtain the real-time voltage value output by the Hall sensor array; Convert the real-time voltage value into real-time magnetic field strength through the calibration coefficient.

4. The magnetic field adjustment method of a magnetic levitation planar motor according to claim 3, characterized in that, The mover assembly (10) further comprises a reinforcing layer arranged between the adjustable magnetic array layer (3) and the mover bottom plate (4); the reinforcing layer comprises a reinforcing coil array, and the projection position of the reinforcing coil on the plane corresponds to the position of the permanent magnet array.

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