Magnetic attraction structure of cake-shaped Halbach

Abstract

The invention discloses a cake-shaped Halbach magnetic attraction structure which comprises a cake-shaped permanent magnet formed by splicing nine single magnets and nine single magnets, and the horizontal cross section of the single magnet in the center is square. The magnetizing direction of the single magnetic block in the center is perpendicular to the radial direction, and the magnetizing directions of the other single magnetic blocks are parallel to the radial direction. The nine small magnetic blocks are regularly spliced into a round cake shape, the middle magnetic blocks vertically punch the surrounding magnetic blocks to magnetize inwards or outwards according to the vertical magnetizing direction of the central magnetic block, the adsorption force is 4% better than that of a traditional magnetizing mode under the same size, the round cake-shaped magnetic induction distribution range is concentrated and uniform, and the magnetic induction efficiency is greatly improved. And in the using process, the working stability of the robot is improved due to the influence of magnetic force on surrounding elements or constructed magnetic force, the controllability and predictability of the magnet adsorption range are improved, and conditions are provided for the robot to achieve accurate wall surface walking.

Description

Technical Field

[0001] The invention relates to the field of magnetic adsorption technology, and in particular to a disk-shaped, pancake-shaped Halbach magnetic adsorption structure. Background Art

[0002] The Halbach Array is a circular Halbach magnetic attraction structure, which is an approximate ideal structure in engineering. Its goal is to generate the strongest magnetic field with the least amount of magnets. In 1979, American scholar Klaus Halbach discovered this special permanent magnet structure while doing electron acceleration experiments. He gradually improved this structure and eventually formed the so-called "Halbach" magnet. The traditional linear Halbach array is widely used in the adsorption structure of engineering machinery and special equipment. Another form is to optimize the size of the traditional linear type, change the linear type to an arc type, set it close to the inner side of the moving wheel and cooperate with the wheel, and move the magnet position from the chassis to the wheel side. This can reduce the air gap of the magnet and increase the adsorption force while leaving more chassis space for carrying equipment. Another type is the circular Halbach array, which concentrates the magnetic field on the motor to enhance the magnetic field on one side, greatly improving the motor's rotational efficiency. Inverting the arrangement enhances the magnetic field on the outside, which is used in the design of permanent magnetic attraction wheels. Magnets with different magnetization directions are arranged in a specific ring shape and fixed to the inside of the wheel hub in a specific manner, thus designing a permanent magnetic wheel with adsorption capabilities. Finally, there is the planar Halbach array, which is used in planar motors and magnetic levitation.

[0003] like Figure 1 As shown in the figure, Fang Haifeng et al. proposed a variable magnetic gap adsorption structure based on a Halbach square permanent magnet array to achieve the adjustability of the permanent magnetic adsorption unit of a hull-climbing robot. This type of permanent magnet uses a 3×3 Halbach array similar to the traditional strip Halbach array connected end to end to form a square, and is fixed with yokes on one side and circumferentially.

[0004] Existing wall-climbing robots using magnetic adsorption structures either employ a single magnet or a traditional Halbach permanent magnet array. Single magnets have weak adsorption force and low magnetic energy utilization efficiency. Traditional Halbach arrays are mostly single-row linear or simply optimized for size, such as arcs or squares. These adsorption structures have simple magnetic circuits and dispersed and uneven field strength distribution, which can easily affect the normal operation of other robot components. Furthermore, optimized structural dimensions result in low space utilization. Summary of the Invention

[0005] In view of the shortcomings of the prior art, the present invention provides a circular Halbach magnetic attraction structure to solve the technical problems of the prior art in that the magnetic circuit is simple and the field strength distribution is dispersed and uneven.

[0006] The present invention provides a pancake-shaped Halbach magnetic attraction structure, comprising: 9 single magnets, which are assembled into a pancake-shaped permanent magnet. The horizontal cross-section of the central single magnetic block is square; the magnetization direction of the central single magnetic block is perpendicular to the radial direction, and the magnetization directions of the other single magnetic blocks are parallel to the radial direction.

[0007] Furthermore, when the magnetization direction of the central single magnetic block is toward the direction of the object to be attracted, the magnetization directions of the other single magnetic blocks are toward the center of the magnetic attraction structure.

[0008] Furthermore, when the magnetization direction of the central single magnetic block is directed away from the object to be attracted, the magnetization directions of the other single magnetic blocks are directed away from the center of the magnetic attraction structure.

[0009] Furthermore, the angle between the magnetization directions of two adjacent single magnetic blocks around the central single magnetic block is 45°.

[0010] Furthermore, the diameter range of the magnetic attraction structure is: 80mm~180mm; the height range is: 10mm~70mm.

[0011] The present invention also provides a magnetic adsorption device, comprising: a circular Halbach magnetic attraction structure, a yoke, and a lifting assembly;

[0012] The yoke is barrel-shaped, and the magnetic structure is located inside the barrel-shaped yoke. The non-magnetic surface and the circumference of the magnetic structure are in contact with the inner wall of the barrel-shaped yoke, and the depth of the barrel-shaped yoke is less than or equal to the height of the magnetic structure. The lifting component lifts the yoke by at least one point, driving the magnetic structure to approach and move away from the object to be adsorbed.

[0013] The present invention also provides a design method for a magnetic adsorption device, including: a circular Halbach magnetic adsorption structure and a yoke size design process, specifically:

[0014] Step A1: Determine the minimum adsorption force required by the magnetic structure;

[0015] Step A2: Obtain the magnetic structure and yoke size corresponding to the minimum adsorption force;

[0016] Step A3: Obtain a curve diagram of adsorption efficiency and adsorption force corresponding to each variable size through the control variable method and constraint conditions;

[0017] Step A4: Obtain the size corresponding to the maximum adsorption efficiency within the preset range of the minimum adsorption force in each curve graph;

[0018] Step A5: Calculate the adsorption force corresponding to the current magnetic structure and the size of the yoke.

[0019] When the adsorption force is greater than or equal to the minimum adsorption force, the current magnetic structure and yoke size are used as the final design size;

[0020] When the adsorption force is less than the minimum adsorption force, the corresponding dimensions are adjusted in sequence starting from the curve graph with the smallest curve change rate, and return to step 5, wherein the adjustment method is specifically: adjust the dimension with the corresponding preset adjustment dimension, and when the dimension corresponding to the current curve graph has reached the maximum adjustable value, adjust the dimension in the next curve graph.

[0021] Furthermore, the constraints in step A3 are:

[0022]

[0023] Where f(d) is the selection function of the four parameter values; MaxFv is the maximum adsorption efficiency; D is the diameter of the magnetic structure; h is the height of the magnetic structure; w1 is the bottom thickness of the yoke; w2 is the side wall thickness of the yoke; F m For adsorption force.

[0024] Furthermore, in step A1, when the minimum adsorption force required to be provided by the magnetic structure is greater than the adsorption force corresponding to the maximum size in the constraint condition, the current minimum adsorption force is split into several sub-adsorption forces, each sub-adsorption force is provided by a magnetic structure, and the size of the magnetic structure and yoke iron corresponding to each sub-adsorption force is calculated through steps A2-A5.

[0025] The present invention also provides a wall-climbing robot, comprising: a robot body and a magnetic adsorption device.

[0026] Beneficial effects of the present invention:

[0027] The present invention uses nine small magnetic blocks regularly arranged into a circular shape. The middle magnetic block vertically magnetizes the surrounding magnetic blocks, which are evenly distributed inward or outward according to the direction of the vertical magnetization of the central magnetic block. The adsorption force is 4% better than that of traditional magnetization forms of the same size. The magnetic induction distribution cloud map shows that the designed circular magnetic induction distribution range is concentrated and uniform. While the adsorption force is increased, the concentrated range reduces the magnetic influence of the magnet on surrounding components or structures during use, improving the working stability of the robot. The uniform and approximately circular distribution form improves the controllability and predictability of the magnet adsorption range, providing conditions for the robot to achieve precise wall walking. The optimal size range of the circular magnet of the present invention is determined through simulation calculation of adsorption efficiency. The smaller size range saves the cost of manufacturing expensive magnets. The barrel-shaped iron stabilizes the magnet while facilitating connection with the lifting mechanism. The magnet size optimization method provided by the present invention can design the most suitable and economical magnet size for different engineering requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The features and advantages of the present invention will be more clearly understood by referring to the accompanying drawings, which are schematic and should not be construed as limiting the present invention in any way. In the accompanying drawings:

[0029] Figure 1 This is a schematic diagram of an existing square 3×3 Halbach array;

[0030] Figure 2 Schematic diagram of a circular Halbach magnetic attraction structure according to a specific embodiment of the present invention;

[0031] FIG3( a ) is a cloud diagram of the field intensity distribution of the present invention in a specific embodiment of the present invention;

[0032] FIG3( b ) is a field intensity distribution cloud diagram of the prior art in a specific embodiment of the present invention;

[0033] Figure 4 2 is a schematic diagram comparing adsorption forces at an air gap of 15-25 mm in a specific embodiment of the present invention;

[0034] Figure 5 is a front view of a magnetic adsorption device in a specific embodiment of the present invention;

[0035] Figure 6 is a three-dimensional schematic diagram of a magnetic adsorption device in a specific embodiment of the present invention;

[0036] FIG7( a ) is a schematic diagram showing the leakage of magnetic flux lines when a yoke is provided in a specific embodiment of the present invention;

[0037] FIG7( b ) is a schematic diagram of magnetic flux leakage when there is no yoke in a specific embodiment of the present invention;

[0038] FIG8( a ) is a graph showing a diameter as a function of the size of the diameter in a specific embodiment of the present invention;

[0039] FIG8( b ) is a graph showing a height-variable dimension in a specific embodiment of the present invention;

[0040] FIG8( c ) is a graph showing the bottom thickness as a function of the size of the bottom in a specific embodiment of the present invention;

[0041] FIG8( d ) is a graph showing the sidewall thickness as a variable dimension in a specific embodiment of the present invention. DETAILED DESCRIPTION

[0042] To make the purpose, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without making any creative efforts shall fall within the scope of protection of the present invention.

[0043] The present invention will be further described below with reference to specific examples. Those skilled in the art will appreciate that these examples are intended only to illustrate the present invention and are not intended to limit the scope of the present invention, and that modifications to various equivalent forms of the present invention fall within the scope defined by the appended claims.

[0044] like Figure 2 As shown, the present invention provides a circular pancake-shaped Halbach magnetic attraction structure, comprising: 9 single magnets, 9 single magnets assembled into a circular pancake-shaped permanent magnet, wherein the horizontal cross-section of the central single magnet is a square; the horizontal cross-sections of the four corner single magnets are fan-shaped; the horizontal cross-sections of the four side single magnets are squares with arc-shaped outer sides, and the distance from the arc top to the opposite side is equal to the side length; the 9 single magnets assembled into a circular pancake-shaped permanent magnet is equivalent to being cut as a whole by 9 3*3 cubic single magnets, with the midpoint of the central single magnet as the center of the circle and three times the sum of the side lengths of the single magnet as the diameter; the central single magnet The magnetizing direction of the magnetic block is perpendicular to the radial direction, and the magnetizing directions of the other monomer magnetic blocks are parallel to the radial direction. When the magnetizing direction of the central monomer magnetic block is toward the direction of the object to be attracted, the magnetizing directions of the other monomer magnetic blocks are toward the center of the magnetic attraction structure of the circular pancake-shaped Halbach; when the magnetizing direction of the central monomer magnetic block is away from the direction of the object to be attracted, the magnetizing directions of the other monomer magnetic blocks are away from the center of the magnetic attraction structure of the circular pancake-shaped Halbach; the angle between the magnetizing directions of two adjacent monomer magnetic blocks around the central monomer magnetic block is 45°, and the specific angle settings are shown in Table 1 below, where the magnet in the positive direction of the x-axis is numbered 1 and arranged counterclockwise.

[0045]

[0046] Table 1

[0047] As shown in the comparison between FIG3(a) and FIG3(b), the field strength distribution of the magnetic attraction structure of the circular Halbach of the present invention is more concentrated and uniform. The more concentrated it is, the smaller the influence of the magnetic force on other equipment will be, and the more uniform it is, the greater the stability of the robot's walking adsorption.

[0048] like Figure 4 As shown, the adsorption force provided by the shape and magnetization direction of the permanent magnet of the present invention is significantly greater than that of the traditional strip type at all stages of air gap adjustment.

[0049] like Figure 5 、 6 As shown, a specific embodiment of the present invention further provides a magnetic adsorption device, comprising: the above-mentioned circular Halbach magnetic attraction structure 1, a yoke 2 and a lifting assembly;

[0050] The yoke 2 is barrel-shaped, and the circular Halbach magnetic structure 1 is positioned within the barrel-shaped yoke 2. The non-magnetic surface and circumference of the circular Halbach magnetic structure 1 are in contact with the inner wall of the barrel-shaped yoke 2. The depth of the barrel-shaped yoke 2 is less than or equal to the height of the circular Halbach magnetic structure 1. Three internally tapped bosses 21 are provided on the top of the yoke 2 for mating with the screw 31 of the lifting mechanism. The lifting assembly includes a motor 34, a driving wheel 32, three driven wheels 33, and three screws 31. The three driven wheels 33 are distributed in a triangle, the output shaft of the motor 34 is coaxially connected to the driving wheel 32, and the driving wheel 32 is engaged with the three driven wheels 33 at the same time. One end of the screw 31 is screwed into the center of the driven wheel 33 and is coaxial with the driven wheel 33, and the other end of the screw 31 is screwed into the boss 21. The motor 34 drives the driving wheel 32 to drive the driven wheel 33 to rotate. The thread in the center of the driven wheel 33 cooperates with the screw 31, and the yoke 2 is lifted by a three-point lifting method, driving the round-shaped Halbach magnetic attraction structure 1 to approach and move away from the object to be adsorbed.

[0051] like Figure 7(a) 、 7(b) As shown in the figure, a two-dimensional static magnetostrictive simulation model was constructed in Ansys software to detect the influence of the yoke on the magnetic flux lines. After the yoke was installed, the upper magnetic leakage of the permanent magnet was completely guided, and the magnetic leakage on both sides was significantly improved.

[0052] A specific embodiment of the present invention further provides a design method for a magnetic adsorption device, including: a circular Halbach magnetic attraction structure and a yoke size design process, wherein the size includes: a diameter D of the circular Halbach magnetic attraction structure, a height H of the circular Halbach magnetic attraction structure, a bottom thickness w1 of the yoke, and a side wall thickness w2 of the yoke. The specific steps are:

[0053] Step A1: Determine the minimum adsorption force required by the circular Halbach magnetic structure;

[0054] Due to the size and weight of the wall-climbing robot, a larger adsorption force is required to achieve wall climbing. When the size of the optimal constraint range provided by the present invention cannot directly provide the required adsorption force, it is possible to consider using multiple magnetic adsorption devices to achieve the required adsorption force. At this time, the current minimum adsorption force is split into several sub-adsorption forces. The splitting method can be carried out according to actual conditions. It only needs to ensure that the size corresponding to the adsorption force is within the constraint range. The size of the circular Halbach magnetic structure and the yoke iron corresponding to each sub-adsorption force is calculated through steps A2-A5.

[0055] Step A2: Obtain the dimensions of the circular Halbach magnetic structure and yoke corresponding to the minimum adsorption force. These dimensions are estimated using conventional models. The accuracy of these dimensions is low, and the corresponding adsorption efficiency may not be optimal, requiring optimization in subsequent steps.

[0056] Step A3: Obtain a curve diagram of adsorption efficiency and adsorption force corresponding to each variable size through the control variable method and constraint conditions;

[0057] In order to facilitate the study of the effect of size parameter changes on unit magnetic adsorption efficiency, the adsorption force per unit volume, that is, the formula for adsorption efficiency is defined as:

[0058]

[0059] Where, F v is the adsorption efficiency, which is proportional to the permanent magnet utilization rate; F max is the generated adsorption force; V is the volume of the circular Halbach magnetic structure;

[0060] The variable method is to change one of the parameters and keep the other parameters fixed;

[0061] As shown in Figures 8(a), 8(b), 8(c), and 8(d), the diameter D of the circular Halbach magnetic structure, the height H of the circular Halbach magnetic structure, the bottom thickness w1 of the yoke, and the side wall thickness w2 of the yoke each correspond to a curve graph; in Figure 8(a), the diameter is a variable dimension; in Figure 8(b), the height is a variable dimension; in Figure 8(c), the bottom thickness is a variable dimension; and in Figure 8(d), the side wall thickness is a variable dimension.

[0062] Since the size in step 2 is estimated, after software simulation, the adsorption force corresponding to the size will be greater or less than the minimum adsorption force.

[0063] The constraints are:

[0064]

[0065] Where f(d) is the selection function of the four parameter values; MaxFv is the maximum adsorption efficiency; D is the diameter of the circular Halbach magnetic attraction structure; H is the height of the circular Halbach magnetic attraction structure; w1 is the bottom thickness of the yoke; w2 is the side wall thickness of the yoke; F m For adsorption force.

[0066] Step A4: Obtain the size corresponding to the maximum adsorption efficiency within the preset range of the minimum adsorption force in each curve graph. The preset range can be set to a positive 10% to avoid the situation where the adsorption force corresponding to the maximum adsorption efficiency is much greater than the minimum adsorption force as shown in Figure 8(b). The setting of the preset range can effectively improve rationality.

[0067] Step A5: Calculate the current circular Halbach magnetic structure and the corresponding adsorption force of the yoke size.

[0068] When the adsorption force is greater than or equal to the minimum adsorption force, the current circular Halbach magnetic structure and the size of the yoke are used as the final design dimensions;

[0069] When the adsorption force is less than the minimum adsorption force, the corresponding dimensions are adjusted in sequence starting from the curve graph with the smallest curve change rate, and return to step 5, wherein the adjustment method is specifically: adjust the dimension with the corresponding preset adjustment dimension. When the dimension corresponding to the current curve graph has reached the maximum adjustable value, adjust the dimension in the next curve graph, wherein the corresponding preset adjustment dimensions include: the preset adjustment dimensions of the diameter and height adjustment of the circular Halbach magnetic structure are: 5mm; the preset adjustment dimension of the yoke iron size is: 1mm.

[0070] The method of the present invention is described below by way of examples:

[0071] The material of the circular Halbach magnetic structure is neodymium iron boron N35, and each magnetic block is magnetized according to the designed magnetization direction; the yoke material is Q235; the surface material of the object to be adsorbed is steel1008; the air gap is set to 15mm; and the minimum adsorption force is 953.946N.

[0072] The estimated size of the circular Halbach magnetic structure can be obtained based on the required minimum adsorption force, as follows

[0073] As shown in Table 2:

[0074] size D / mm h / mm <![CDATA[w1 / mm]]> <![CDATA[w2 / mm]]> Initial value 150 25 5 5

[0075] Table 2

[0076] The size does not exceed the constraint range, and there is no need to split the minimum adsorption force.

[0077] The constraints at this time are:

[0078]

[0079] Using the four basic dimensions of the circular Halbach magnetic attraction structure (direction D), the height H of the circular Halbach magnetic attraction structure, the bottom thickness w1 of the yoke, and the side wall thickness w2 of the yoke as variable parameters, combined with the adsorption efficiency formula, we constructed the adsorption efficiency and adsorption force curves corresponding to the four variable parameters as shown in Figures 8(a), 8(b), 8(c), and 8(d).

[0080] As shown in Figure 8(a), the magnet diameter is set as the variable parameter, F / F v Curve that changes with diameter D. The adsorption force F increases with the increase of D, in direct proportion. When 80≤D≤120mm, the adsorption force per unit volume F v As D increases, the magnetic energy utilization efficiency increases gradually; when 120≤D≤180mm, F v It starts to decrease as D increases. At this point, the utilization efficiency of magnetic energy begins to decrease. The increase in D only serves to increase the adsorption force of the permanent magnet, while the utilization rate of magnetic energy begins to gradually decrease. At this time, the diameter D is selected as 120mm. The adsorption force corresponding to 120mm does not exceed 10% of the minimum adsorption force, so 120mm can be used as the optimized diameter.

[0081] As shown in Figure 8(b), the magnet height is set as the variable parameter, F / F v Curve that changes with the height h of the magnet. The adsorption force F increases with the height h. When h>40mm, the growth rate of the adsorption force begins to slow down gradually; when 10≤h≤20mm, the adsorption force per unit volume F v As h increases, it increases sharply, and the corresponding magnetic energy utilization efficiency increases rapidly; when 20≤h≤40mm, F v The growth rate begins to slow down; when h≥40mm, F v It begins to drop rapidly, and the magnetic energy utilization efficiency gradually decreases. At this time, the highest adsorption efficiency is at a height of 40mm, but the corresponding adsorption force exceeds 10% of the minimum adsorption force, resulting in excessive adsorption force. Therefore, 40mm is not selected as the optimized height. The height corresponding to the second highest adsorption efficiency, 22mm, is selected. The corresponding adsorption force of 22mm does not exceed 10% of the minimum adsorption force, so 22mm can be used as the optimized height.

[0082] As shown in Figure 8(c), the thickness of the yoke bottom is set as the variable parameter, F / F v Curve that changes with the magnet height w1. The adsorption force F decreases with the increase of the thickness of the upper part of the yoke, which is inversely proportional. Adsorption force F per unit volumev As w1 increases, it gradually decreases, and the deceleration gradually slows down. Because it is an inversely proportional relationship, the adsorption efficiency corresponding to the minimum adsorption force at this time is the maximum adsorption efficiency. The 2mm corresponding to the adsorption force can be used as the optimized bottom thickness.

[0083] As shown in Figure 8(d), the circumferential thickness of the yoke is set as the variable parameter, F / F v Curve that changes with the magnet height w2. The adsorption force F reaches its highest point F = 1.56 kN when w2 = 1 mm. When w2 ≥ 1 mm, the adsorption force begins to decrease slowly and remains almost unchanged when it reaches 5 mm. Adsorption force per unit volume F v As w2 increases, it decreases. When w2 ≥ 2mm, the reduction rate begins to slow down, and the change in magnetic energy utilization gradually stabilizes. Similar to the height selection, the adsorption force corresponding to the maximum adsorption efficiency is excessive, and 2mm is selected as the optimized side wall thickness.

[0084] Through the above examples, while maximizing magnetic energy utilization efficiency and minimizing magnet volume, various parameters of the magnetic adsorption device were optimized based on the installation location, space requirements, and adsorption force requirements of the wall-climbing robot. The optimization results are shown in Table 3 below. Adsorption force simulations were conducted again for the optimized magnetic adsorption device at air gaps of 15-25 mm, resulting in an adsorption force range of 431-961 N, meeting the wall-climbing robot's full-power wall adhesion requirement of 953.946 N. The optimized magnet mass was reduced by 36%, adsorption efficiency was increased by 11.7%, and the efficiency of the adsorption module was enhanced.

[0085] parameter Before optimization After optimization Magnet diameter D / mm 150 120 Magnet height h / mm 25 22 <![CDATA[Yoke thickness w1 / mm]]> 5 2 <![CDATA[Yoke thickness w2 / mm]]> 5 2 Magnet mass G / kg 3.3 2.11 Equivalent adsorption efficiency Fv (N / cm^3) 3.33 3.72

[0086] Table 3

[0087] A specific embodiment of the present invention further provides a wall-climbing robot, comprising: a robot body and a magnetic adsorption device. The number of the magnetic adsorption devices can be determined according to a design method for the magnetic adsorption device.

[0088] Although the embodiments of the present invention have been described with reference to the accompanying drawings, those skilled in the art may make various modifications and variations without departing from the spirit and scope of the present invention. Such modifications and variations are all within the scope defined by the appended claims.

Claims

1. A circular Halbach magnetic structure, characterized in that: include: 9 single magnets, 9 single magnetic blocks are assembled into a pancake-shaped permanent magnet, among which the horizontal cross-section of the central single magnetic block is a square; the magnetizing direction of the central single magnetic block is perpendicular to the radial direction, and the magnetizing directions of the other single magnetic blocks are parallel to the radial direction.

2. The circular Halbach magnetic attraction structure according to claim 1, characterized in that: When the magnetization direction of the central single magnetic block is toward the direction of the object to be attracted, the magnetization directions of the other single magnetic blocks are toward the center of the magnetic attraction structure.

3. The circular Halbach magnetic attraction structure according to claim 1, characterized in that: When the magnetization direction of the central single magnetic block is directed away from the object to be attracted, the magnetization directions of the other single magnetic blocks are directed away from the center of the magnetic attraction structure.

4. The disk-shaped Halbach magnetic attraction structure according to any one of claims 1 to 3, characterized in that: The angle between the magnetization directions of two adjacent single magnetic blocks around the central single magnetic block is 45°.

5. The circular Halbach magnetic attraction structure according to claim 1, characterized in that: The diameter of the circular Halbach magnetic structure ranges from 80 mm to 180 mm, and the height ranges from 10 mm to 70 mm.

6. A magnetic adsorption device, characterized in that: include: The magnetic attraction structure, yoke and lifting assembly of the pancake-shaped Halbach according to any one of claims 1 to 5; The yoke is barrel-shaped, the magnetic structure is located inside the barrel-shaped yoke, the non-magnetic surface and the circumference of the magnetic structure are in contact with the inner wall of the barrel-shaped yoke, and the depth of the barrel-shaped yoke is less than or equal to the height of the magnetic structure; The lifting assembly lifts the yoke by at least a little lifting, driving the magnetic attraction structure to move closer to and away from the object to be adsorbed.

7. A method for designing a magnetic adsorption device according to claim 6, characterized in that: include: The design process of the circular Halbach magnetic structure and yoke size is as follows: Step A1: Determine the minimum adsorption force required by the magnetic structure; Step A2: Obtain the magnetic structure and yoke size corresponding to the minimum adsorption force; Step A3: Obtain a curve diagram of adsorption efficiency and adsorption force corresponding to each variable size through the control variable method and constraint conditions; Step A4: Obtain the size corresponding to the maximum adsorption efficiency within the preset range of the minimum adsorption force in each curve graph; Step A5: Calculate the adsorption force corresponding to the current magnetic structure and the size of the yoke. When the adsorption force is greater than or equal to the minimum adsorption force, the current magnetic structure and yoke size are used as the final design size; When the adsorption force is less than the minimum adsorption force, the corresponding dimensions are adjusted in sequence starting from the curve graph with the smallest curve change rate, and return to step 5, wherein the adjustment method is specifically: adjust the dimension with the corresponding preset adjustment dimension, and when the dimension corresponding to the current curve graph has reached the maximum adjustable value, adjust the dimension in the next curve graph.

8. The design method of the magnetic adsorption device according to claim 7, characterized in that: The constraints in step A3 are: Where f(d) is the selection function of the four parameter values; MaxFv is the maximum adsorption efficiency; D is the diameter of the magnetic structure; h is the height of the magnetic structure; w1 is the bottom thickness of the yoke; w2 is the side wall thickness of the yoke; F m For adsorption force.

9. The method for designing a magnetic adsorption device according to claim 7 or 8, wherein: In step A1, when the minimum adsorption force required to be provided by the magnetic structure is greater than the adsorption force corresponding to the maximum size in the constraint condition, the current minimum adsorption force is split into several sub-adsorption forces, each sub-adsorption force is provided by a magnetic structure, and the size of the magnetic structure and yoke iron corresponding to each sub-adsorption force is calculated through steps A2-A5.

10. A wall-climbing robot, characterized in that: include: A robot body and the magnetic adsorption device as claimed in claim 6.

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