Enhanced electromagnetic drive systems, devices, and methods that can generate a variety of electromagnetic fields

Abstract

The present disclosure relates to an electromagnetic driving system for solving the clinical need for different magnetic field modes for assisting drug delivery, while the prior art is difficult to generate different magnetic field modes using one electromagnetic driving system. The present disclosure proposes a micro-robot magnetic manipulation system with an expandable spherical large working space, which adopts a modular mechanical design and can generate gradient magnetic fields, uniform magnetic fields, rotating magnetic fields, oscillating magnetic fields, and dispersed gradient magnetic fields in the spherical space, thereby facilitating the manipulation of the deformation and movement of micro-robots of any shape and quantity, and delivering drugs to the corresponding positions in the human body.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to an electromagnetic driving system of a micro robot, in particular to an electromagnetic driving system, device and method capable of generating multiple electromagnetic fields, which can provide a large operation space required for magnetizing a robot to deliver drugs in the body. BACKGROUND

[0002] With the development of biomedical engineering, electromagnetic driving has become a safe and efficient driving method. Electromagnetic driving robots have the advantages of remote control and non-invasive / minimally invasive, and have important application value in magnetic robot operation. The development of clinical surgery is closely related to the progress of engineering technology. Specifically, in the field of non-invasive or minimally invasive surgery, it is particularly reflected in the magnetic driving device driving the magnetic robot to deliver drugs or perform surgery. The internal environment of the human body includes different areas, such as easily accessible intraocular space to complex intravascular systems that are not easy to access, or large enough natural cavities and channels in the human body, such as joint cavities or gastrointestinal tracts, which are ideal working spaces for the movement of magnetic robots. SUMMARY

[0003] The purpose of the present disclosure is to provide a magnetic manipulation system of a micro robot with an expandable spherical large working space, which can generate gradient magnetic fields, uniform magnetic fields, rotating magnetic fields, oscillating magnetic fields, and dispersed gradient magnetic fields in the spherical space, thereby manipulating the deformation and movement of micro robots of any shape and quantity, and delivering drugs to corresponding positions in the human body.

[0004] To achieve the above-mentioned purpose, the electromagnetic driving system provided by the present disclosure comprises four closed-loop magnetic bridges, each magnetic bridge being connected with a first electromagnetic device and a second electromagnetic device; the first electromagnetic device and the second electromagnetic device are the same and each comprises a conical head, a first anti-magnetic dissipation device, an iron core, an electromagnetic coil, and a second anti-magnetic dissipation device, wherein: the tip radius of the conical head is greater than zero, the bottom of the cone is fixed with the first end of the iron core, the iron core is located in the electromagnetic coil, and the first anti-magnetic dissipation device is clamped between the conical head and the electromagnetic coil; the second end of the iron core and the second segment or the fourth segment of the magnetic bridge are fixed, and the second anti-magnetic dissipation device is clamped between the electromagnetic coil and the magnetic bridge; the size of the working space is adjusted and the gradient of the magnetic field is enhanced by an extension rod between the center of the conical head and the iron core, and the shortest length of the extension rod is determined by the minimum length of the end of the fixed conical head, and the longest length is determined by the minimum working space.

[0005] In an embodiment of the above-mentioned system technical solution, the magnetic bridge is installed on a base, and the base has holes capable of adjusting the installation position, and by moving the four groups of magnetic bridges outward at the same time, the working space can be increased.

[0006] In an embodiment of the system, the magnetic bridge comprises a first segment, a second segment, a middle segment, a third segment and a fourth segment connected in sequence, the first segment and the fourth segment are parallel, the second segment and the third segment are equal in length, and the second segment and the third segment form an angle with the middle segment, a first electromagnetic device is connected to the second segment, and a second electromagnetic device is connected to the third segment; the first segment and the fourth segment ensure the enhanced gradient magnetic field in the vertical direction.

[0007] In an embodiment of the system, the length of the extension rod is 20-30 mm.

[0008] In an embodiment of the system, the weight of the electromagnetic driving system is less than 70 kg, and the height is less than 500 mm.

[0009] As can be seen from the system, the disclosure further proposes an electromagnetic device, which comprises a conical head, a first anti-magnetic dissipation device, an iron core, an electromagnetic coil, and a second anti-magnetic dissipation device, wherein: the radius of the conical tip of the conical head is greater than zero, the conical bottom is fixed with the first end of the iron core, the iron core is located in the electromagnetic coil, and the first anti-magnetic dissipation device is clamped between the conical head and the electromagnetic coil; the second end of the iron core is fixed with the second segment or the fourth segment of the magnetic bridge, and the second anti-magnetic dissipation device is clamped between the electromagnetic coil and the magnetic bridge; the size of the working space is adjusted and the gradient of the magnetic field is enhanced by the extension rod between the conical head and the center of the iron core, and the shortest length of the extension rod is determined by the minimum length of the fixed end of the conical head, and the longest length is determined by the minimum working space.

[0010] As can be seen from the system, the disclosure further proposes a method for generating a magnetic field in the working space of an electromagnetic driving system, the electromagnetic driving system comprising four closed-loop magnetic bridges, each magnetic bridge being connected with a first electromagnetic device and a second electromagnetic device, the first electromagnetic device and the second electromagnetic device being the same and comprising a conical head, a first anti-magnetic dissipation device, an iron core, an electromagnetic coil, and a second anti-magnetic dissipation device, wherein: the radius of the conical tip of the conical head is greater than zero, the conical bottom is fixed with the first end of the iron core, the iron core is located in the electromagnetic coil, and the first anti-magnetic dissipation device is clamped between the conical head and the electromagnetic coil; the second end of the iron core is fixed with the second segment or the fourth segment of the magnetic bridge, and the second anti-magnetic dissipation device is clamped between the electromagnetic coil and the magnetic bridge; the size of the working space is adjusted and the gradient of the magnetic field is enhanced by the extension rod between the conical head and the center of the iron core, and the shortest length of the extension rod is determined by the minimum length of the fixed end of the conical head, and the longest length is determined by the minimum working space; the method comprises: generating a preset magnetic field mode by operating the first electromagnetic device and / or the second electromagnetic device at a preset position, the magnetic field mode comprising an enhanced gradient magnetic field, a uniform magnetic field, a rotating magnetic field, an oscillating magnetic field, and a dispersed gradient magnetic field.

[0011] In the above method technical solution, the first electromagnetic device and / or the second electromagnetic device at the preset position are driven to generate a preset magnetic field mode, including: driving a pair of electromagnetic devices on a magnetic bridge in opposite directions to generate a magnetic loop, thereby generating a horizontal direction enhanced gradient magnetic field; dividing the four electromagnetic devices in the upper half or the lower half into two groups, taking two adjacent electromagnetic devices as one group, and driving the two groups of electromagnetic devices such that the current direction of one group of electromagnetic devices is opposite to that of the other group, to generate a vertical direction enhanced gradient magnetic field; driving two electromagnetic devices satisfying a preset distance to generate a uniform magnetic field, the two electromagnetic devices satisfying the preset distance being two electromagnetic devices on the second segment and the third / second segment of the opposite magnetic bridge, or two electromagnetic devices on the second segment and the third segment of the adjacent magnetic bridge; driving four preset electromagnetic devices to generate the rotating magnetic field by time division excitation, the four preset electromagnetic devices being the electromagnetic devices on the second segment of each magnetic bridge, or the electromagnetic devices on the third segment of each magnetic bridge, or four electromagnetic devices on the opposite magnetic bridge, or four electromagnetic devices on the adjacent two magnetic bridges; and driving the four preset electromagnetic devices to generate the oscillating magnetic field by satisfying the following excitation function: , , , wherein, is the current amplitude, a constant parameter , is the oscillation frequency, is the time, the oscillation angle , by adjusting the constant parameter , the oscillation angle can be changed; the four preset electromagnetic devices are four electromagnetic devices on the second segment of each magnetic bridge, or four electromagnetic devices on the third segment of each magnetic bridge, or four electromagnetic devices on the opposite two magnetic bridges, or four electromagnetic devices on the adjacent two magnetic bridges; driving two pairs of electromagnetic devices on the opposite magnetic bridge such that the direction of the magnetic loop generated by one pair of electromagnetic devices is opposite to that of the other pair, to generate the dispersed gradient magnetic field; or dividing two adjacent pairs of four pairs of electromagnetic devices into one group, and driving the two groups of electromagnetic devices such that the direction of the magnetic loop formed by the two pairs of electromagnetic devices in one group is opposite to that of the two pairs in the other group, to generate the dispersed gradient magnetic field.

[0012] The beneficial technical effects of the present disclosure are: (1) multiple specific magnetic field modes can be generated, including uniform magnetic field, a dispersed gradient magnetic field, and an enhanced gradient magnetic field. (2) A large magnetic field gradient (16T / m) can be achieved under the drive of a small current (10A), and the micro-robot can be driven in any form to cooperate with a large space to achieve medical applications, such as knee injury treatment. The system can be configured in the knee joint, and the working space of the system is located in the knee joint. (3) The gradient force in the vertical direction is considered in the three-dimensional space, and the gradient force in the vertical direction is enhanced without affecting the gradient force in the horizontal direction. (4) The electromagnetic drive system under the structure of the present disclosure can generate a large magnetic field under a small size (the height can be lower than 500mm). BRIEF DESCRIPTION OF DRAWINGS

[0013] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed in the embodiment description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0014] Figure 1 It is a side view of the electromagnetic drive system structure in an embodiment.

[0015] Figure 2 It is an installation diagram of an electromagnetic device on a magnetic bridge in an embodiment.

[0016] Figure 3 It is an exploded view of an electromagnetic device in an embodiment.

[0017] Figure 4 It is a schematic diagram of the oscillating magnetic field generated by the electromagnetic drive system in an embodiment. DETAILED DESCRIPTION

[0018] Magnetic force driving methods include magnetic torque driving and magnetic force gradient driving. Although the torque driving method is more energy efficient than the magnetic force driving method, the torque driving method is heavily dependent on the design of the magnetic robot. The structural design of the torque-driven microrobot must meet the requirement of converting the applied torque into translational force. A typical design is a helical structure that mimics the bacterial flagellum. Another is a fish-like structure that takes advantage of the torque generated by the oscillating magnetic field to move forward. Due to the limitations of the structural design, it is difficult to achieve drug loading by simply using the torque driving method. A typical magnetic robot design for drug delivery uses a spiky porous spherical structure driven under a magnetic field gradient. The classic design, such as Octomag (Kummer, Michael P., et al. "OctoMag: An electromagnetic system for 5-DOF wireless micromanipulation." IEEE Transactions on Robotics 26.6 (2010): 1006-1017), which is intended for ophthalmic surgery, can generate a 3D gradient field. However, due to the low efficiency characteristics of the gradient field, this design is difficult to use in medical scenarios that require large gradient forces.

[0019] Based on this, the present disclosure proposes an electromagnetic driving system, which comprises a first electromagnetic device, a second electromagnetic device, and four magnetic bridges; each of the magnetic bridges comprises a first segment, a second segment, an intermediate segment, a third segment, and a fourth segment connected in sequence, the first segment and the fourth segment are parallel, the second segment and the third segment are equal in length, and the second segment, the third segment, and the intermediate segment form an included angle, the first electromagnetic device is connected to the second segment, and the second electromagnetic device is connected to the third segment; the first electromagnetic device and the second electromagnetic device are the same and each comprises a conical head, a first anti-magnetic dissipation device, an iron core, an electromagnetic coil, and a second anti-magnetic dissipation device, wherein: the radius of the tip of the conical head is greater than zero, the bottom of the cone is fixed with the first end of the iron core, the iron core is located in the electromagnetic coil, and the first anti-magnetic dissipation device is clamped between the conical head and the electromagnetic coil; the second end of the iron core and the second segment or the third segment of the magnetic bridge are fixed, and the second anti-magnetic dissipation device is clamped between the electromagnetic coil and the magnetic bridge; by energizing the first electromagnetic device and / or the second electromagnetic device at a preset position, a preset magnetic field mode can be generated, and the magnetic field mode includes an enhanced gradient magnetic field, a uniform magnetic field, a rotating magnetic field, an oscillating magnetic field, and a dispersed gradient magnetic field.

[0020] The technical solutions of the present application will be described in detail below with reference to the drawings. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by a person of ordinary skill in the art without creative labor fall within the scope of protection of the present application.

[0021] The whole electromagnetic driving system can have 4 pairs of same electromagnetic devices, Figure 1 The side view of the electromagnetic driving system structure, Figure 2 The installation diagram of the electromagnetic device on a magnetic bridge is shown. Each electromagnetic device is installed on a magnetic bridge, and each pair of electromagnetic devices is located on a magnetic bridge. The magnetic bridge is installed on the base, which includes the lower base 400 and the large base 402. Each magnetic bridge is installed on the lower base 400 belonging to the magnetic bridge, and the 4 lower bases 400 are installed on the large base 402 of the whole system. The large base and the lower base have holes 401 that can adjust the installation position of the magnetic bridge.

[0022] Each of the magnetic bridges includes a first segment 301, a second segment 302, an intermediate segment 303, a third segment 304, and a fourth segment 305 connected in sequence. The first segment and the fourth segment are parallel, the second segment and the third segment are equal in length, and the second segment and the third segment form an included angle with the intermediate segment. The first electromagnetic device 100 is connected to the second segment, and the second electromagnetic device 200 is connected to the third segment. The structure of the first segment and the fourth segment is a square block, which can make the vertical gradient slightly larger than the horizontal gradient and ensure gradient enhancement.

[0023] Referring to Figure 3 The exploded view of the first electromagnetic device 100 or the second electromagnetic device 200 is shown in FIG. 8. The first electromagnetic device and the second electromagnetic device are the same, and each includes a conical head 101, a first magnetic dispersion prevention device 102, an iron core 104, an electromagnetic coil 103, and a second magnetic dispersion prevention device 105. The conical head has a conical tip with a radius greater than zero, which can determine the working space of the magnetic field as the edge of the magnetic field. The conical bottom is fixed to the first end of the iron core, and the iron core is located in the electromagnetic coil, which clamps the first magnetic dispersion prevention device between the conical head and the electromagnetic coil. The second end of the iron core is fixed to the second segment or the third segment of the magnetic bridge, which clamps the second magnetic dispersion prevention device between the electromagnetic coil and the magnetic bridge. The outer diameter of the first magnetic dispersion prevention device and the second magnetic dispersion prevention device is the same as the diameter of the electromagnetic coil; the inner diameter of the first magnetic dispersion prevention device and the second magnetic dispersion prevention device is the same as the diameter of the iron core.

[0024] By energizing the first electromagnetic device and / or the second electromagnetic device at the preset position, a spherical magnetic field working space can be formed in the whole electromagnetic driving system. The conical tip of the conical head is on the boundary of the working space, and the size of the working space can be adjusted by adjusting the position of the conical head.

[0025] The preset electromagnetic device is energized, including setting which electromagnetic device, or setting which electromagnetic device as a group, setting the working parameters (including setting the excitation current value of the electromagnetic coil, the current direction and the distance between the magnetic core and the center of the working space). The set working parameters can be a group or multiple groups. The first anti-magnetic dispersion device and the second anti-magnetic dispersion device adopt a disc design, which can reduce magnetic field leakage. The wiring terminal is arranged on the side of the second anti-magnetic dispersion device, which can reduce the space occupied by the whole system.

[0026] In the example embodiment, an extension rod is arranged between the conical head and the center of the iron core. The minimum length of the extension rod is determined by the minimum length of the threaded hole for fixing one end of the conical head, and the maximum length is determined by the minimum working space. The optional length of the extension rod is 20-30 mm.

[0027] In some embodiments, the bottom of the conical head has a protruding threaded circular table. Correspondingly, the first end of the iron core has a threaded hole matched with the circular table. In the embodiment with the extension rod, the first end of the extension rod has a threaded hole matched with the bottom of the conical head, and the second end of the extension rod has a threaded circular table matched with the first end of the iron core. The minimum length of the extension rod is determined by the minimum length of the threaded hole for fixing.

[0028] Due to a pair of electromagnetic devices connected by a closed loop supporting the magnetic bridge, a closed magnetic circuit is formed, so that the gradient in the working space can be significantly enhanced by lower magnetic flux leakage, that is, the magnetic field gradient is enhanced based on the closed magnetic circuit. All the magnetic conductive iron columns are made of DT4C material with extremely high magnetic permeability.

[0029] Since the opposite directions of the current in a pair of electromagnetic coils on a magnetic bridge can make the magnetic field direction of the head of each electromagnetic coil opposite, an electromagnetic circuit is formed to establish a connection between the two conductors to enhance the magnetic flux. On this basis, it can be further assumed that the magnetic flux enhancement effect of connecting the two electromagnetic coils with high magnetic permeability material, but the deflection effect caused by the interaction between the two electromagnets is often considered as an error that needs to be corrected, and the use of this effect not only enhances the magnetic field gradient, but also creates a new type of magnetic field.

[0030] In the driving and control of the magnetic field, in order to realize the gradient enhancement effect of the magnetic field, the two electromagnets connected by the magnetic bridge are controlled as a pair to produce four mutually perpendicular magnetic fields in the plane x+ , x- , y+ , y- . In addition, according to the design of the first and fourth segments on the magnetic bridge, the four magnetic heads on the upper side, two by two as a group, can also produce a closed magnetic circuit to produce an upward magnetic field gradientz+ Similarly, the following four magnetic heads, two by two as a group, can also generate a closed magnetic circuit to generate downward magnetic field gradient (B z- ).

[0031] The following magnetic field mode adopted by the example electromagnetic drive system is: 4 magnetic bridges are installed on the large base 402, and electromagnetic devices are installed on the second and third sections of each magnetic bridge. The electromagnetic device installed on the second section is above the electromagnetic device of the third section, and the four electromagnetic devices above are labeled clockwise (from the top) as 1, 3, 5, and 7, respectively. The corresponding lower electromagnetic devices are labeled as 2, 4, 6, and 8.

[0032] The magnetic field strength at any point in the workspace generated by a single electromagnetic coil can be represented by the following formula:

[0033]

[0034] wherein, represents the distance from the coil, is the permeability in vacuum, is the current, is the minimum distance on the coil, d is the distance from a point on the electromagnetic coil to the middle of the magnetic field, is the length of the electromagnetic coil taken, and c is the integral length on the coil.

[0035] For a pair of electromagnetic coils, the magnetic field strength in space is approximately twice the calculated magnetic field strength.

[0036] The torque and force generated at any point in space can be expressed as:

[0037]

[0038] wherein, the coordinate axis o-xyz is the space coordinate system, and the center point of the workspace is the origin: the positive direction of the x-axis is perpendicular to the palm of the right hand, the direction of the four fingers is the positive direction of the y-axis, and the direction of the thumb is the z-axis direction. is the torque, is the magnetic force, is the skew-symmetric matrix, is the magnetic field strength of point p, is the dipole moment, is the gradient of point p in the x direction, is the gradient of point p in the y direction, is the gradient of point p in the z direction, is the required current.

[0039] According to the above formula, if the required torque and force , or given p the magnetic field strength and the magnetic field gradient of a point, the required current can be calculated.

[0040] In an embodiment, according to the dynamics model of the controlled robot, the required torque / force can be known, and according to the known torque / force, the required current can be obtained.

[0041] According to the simulation experiment of Ansys EM, the optimized design of the additional closed-loop support iron column can make the magnetic field and the magnetic field gradient be enhanced by two times.

[0042] The enhanced gradient magnetic field can be generated by driving a pair of electromagnetic devices on a magnetic bridge, and the magnetic flux path can be realized by making the electromagnetic polarity of the pair of electromagnetic devices opposite.

[0043] Specifically, by driving a pair of electromagnetic devices on a magnetic bridge in opposite directions to generate a magnetic loop, the horizontal direction enhanced gradient magnetic field is generated; the four electromagnetic devices in the upper half or the lower half are divided into two groups, the adjacent two electromagnetic devices are taken as a group, and by driving the two groups of electromagnetic devices, the current direction of the electromagnetic devices in one group is opposite to that in the other group, so as to generate the vertical direction enhanced gradient magnetic field.

[0044] For example, in the example electromagnetic driving system, by making the electromagnetic device marked as 1 and the electromagnetic device marked as 2 pass through the current in opposite directions, the horizontal direction enhanced gradient magnetic field can be generated in the working space.

[0045] For example, in the example electromagnetic driving system, for the four electromagnetic devices marked as 1, 3, 5 and 7, the electromagnetic devices marked as 1 and 3 are taken as the first group, and the rest are taken as the second group. By making the current direction of the two electromagnetic devices in the first group the same, and the current direction opposite to that of the second group, the vertical direction enhanced gradient magnetic field can be generated in the working space.

[0046] Under the premise of ensuring the generation of the gradient magnetic field, the generation of the uniform magnetic field is also considered in the design. The magnetic field strength of the distance z from the center of the electromagnetic device conical head to the center of the working space can be expressed as:

[0047]

[0048] N is the number of turns of the electromagnetic coil,R is the radius of the electromagnetic coil.

[0049] According to the above formula, when the distance between the two electromagnetic coils is equal to the radius of the coil, a uniform magnetic field can be generated in the middle of the two electromagnetic coils.

[0050] In the classical theory, it can be derived from the above formula that the most uniform magnetic field can be generated in the working space when the distance between two opposite electromagnetic device coils is equal to the radius of the electromagnetic device coil. However, in the present design, due to the magnetic field enhancement effect of the closed magnetic loop, the distance between two opposite electromagnetic device coils should be much greater than the radius of the electromagnetic coil. Due to the enhancement effect of the magnetic field, a magnetic field strength of about twice the original magnetic field can be generated. Therefore, when the radius of an electromagnetic coil is, for example, 53 mm, the distance between the two opposite electromagnetic device coils in the present design should be about 106 mm. Further, according to the simulation results, the optimal distance is 100 mm, and the present example analyzes the working space with a spherical ball having a diameter of 100 mm.

[0051] Therefore, by configuring the preset two electromagnetic devices to meet the preset distance, the present device can generate a uniform magnetic field. The preset two electromagnetic devices can be two electromagnetic devices located on the second segment and the third segment of the opposite magnetic bridge, or two electromagnetic devices located on the second segment of the opposite magnetic bridge, or two electromagnetic devices located on the third segment of the opposite magnetic bridge, or two electromagnetic devices located on the second segment and the third segment of the adjacent magnetic bridge.

[0052] For example, in the example electromagnetic drive system, the current directions of the two electromagnetic devices are opposite. By making the two electromagnetic devices identified as 1 and 6 meet the preset distance, a uniform magnetic field can be generated. Alternatively, by making the two electromagnetic devices identified as 1 and 5 meet the preset distance, a uniform magnetic field can also be generated. Alternatively, by making the two electromagnetic devices identified as 2 and 6 meet the preset distance, a uniform magnetic field can also be generated. Alternatively, by making the two electromagnetic devices identified as 1 and 4 meet the preset distance, a uniform magnetic field can be generated, and so on.

[0053] According to the ability of the coil to generate a uniform magnetic field, a rotating magnetic field can be achieved by exciting the preset electromagnetic devices in time. For example, the current input of the preset four electromagnetic devices in the counterclockwise direction is as follows: 、 、 、 wherein: is the amplitude of the excitation function, is the frequency of the excitation function, is the phase difference of the excitation function. For example, .

[0054] The above-mentioned preset electromagnetic devices can be the electromagnetic devices of the second segment of each magnetic bridge, or the electromagnetic devices of the third segment of each magnetic bridge, or the four electromagnetic devices on the adjacent two magnetic bridges, or the four electromagnetic devices on the opposite magnetic bridges.

[0055] For example, in the example electromagnetic drive system, by driving four electromagnetic devices identified as 1, 3, 5, 7, or by driving four electromagnetic devices identified as 2, 4, 6, 8, or by driving four electromagnetic devices identified as 1, 2, 3, 4, or by driving four electromagnetic devices identified as 1, 2, 5, 6, a rotating magnetic field can be generated, etc. The currents of the four electromagnetic devices satisfy the above four excitation functions.

[0056] By making the preset electromagnetic devices work to form two opposite direction magnetic loops. In space, two magnetic induction lines are equal in size and opposite in direction, and cancel each other at a point in the working space, forming a minimum point of the magnetic field strength in space, so that a dispersed gradient magnetic field is formed in each direction with the point as the center.

[0057] For example, in the example electromagnetic drive system, using The electromagnetic intensity of the coil represented by the corresponding subscript is activated. If the electromagnetic devices identified as 1, 2 and the electromagnetic devices identified as 5, 6 are made to work, and the magnetic induction lines generated by the electromagnetic devices identified as 1, 2 are opposite to the magnetic induction lines generated by the electromagnetic devices identified as 5, 6, then the center point calculation formula of the dispersed gradient magnetic field is:

[0058]

[0059] It can be understood that the electromagnetic devices identified as 3, 4 and the electromagnetic devices identified as 7, 8 can also be made to work, and the magnetic induction lines generated by the electromagnetic devices identified as 3, 4 are opposite to the magnetic induction lines generated by the electromagnetic devices identified as 7, 8, then the center point calculation formula of the dispersed gradient magnetic field is:

[0060]

[0061] The positions of the dispersed points in the horizontal direction, x-y direction are calculated respectively by using the above formula, so as to determine the positions of the dispersed points in space. Through the design of the dispersed field and the design of the extension rod, the electromagnetic gradient of the whole system can be increased to 16T / m.

[0062] In the vertical direction, if the above four electromagnetic devices 1, 3, 5, 7 are a group, and the corresponding four electromagnetic devices 2, 4, 6, 8 are a group. In the same group, the currents of the adjacent two electromagnetic devices (for example, 1, 3) are in the same direction, and the currents of the remaining two electromagnetic devices (for example, 5, 7) are in the opposite direction. In different groups, the currents of the four electromagnetic devices below are opposite to the currents of the corresponding four electromagnetic devices above. Then, in the z direction, the center point calculation formula of the dispersed gradient magnetic field is:

[0063]

[0064] The position of the dispersion point in the vertical direction, z direction, is calculated using the above formula.

[0065] The oscillating magnetic field is another magnetic field formed based on the uniform magnetic field. The oscillating magnetic field can be generated by inputting current in the clockwise or counterclockwise direction to the four electromagnetic devices of each magnetic bridge second segment, or the four electromagnetic devices of each magnetic bridge third segment, or the four electromagnetic devices of two adjacent magnetic bridges, or the four electromagnetic devices of two diagonal lines, according to the following excitation function: , , , . Wherein, is the current amplitude, and the constant parameter , is the oscillation frequency, is the time, and the oscillation angle can be changed by adjusting the constant parameter .

[0066] The oscillating magnetic field in the local coordinate system i-j-k can be represented as:

[0067]

[0068] Wherein, is the rotation matrix, wherein represents the local coordinate system , represents the global coordinate system .

[0069] For example, in the example electromagnetic driving system, a rotating magnetic field can be generated by driving the four electromagnetic devices with identifiers 1, 3, 5, and 7, or by driving the four electromagnetic devices with identifiers 2, 4, 6, and 8, or by driving the four electromagnetic devices with identifiers 1, 2, 3, and 4, or by driving the four electromagnetic devices with identifiers 1, 2, 5, and 6. The currents of the four electromagnetic devices satisfy the above four excitation functions.

[0070] Figure 4 is a schematic diagram of the oscillating magnetic field generated by the electromagnetic driving system of the above example. Figure 4 1, 2, 5, and 6 in Figure 4 (a), (b), (c), (e), and (f) in , , , , indicate the magnetic flux density generated by the four electromagnetic devices at Figure 4 (d) inis The function diagram of the magnetic flux density B (mT) versus time t (s) is shown in FIG. 3. It can be seen that the maximum magnetic flux density occurs at time t = 0.5 s and t = 1.5 s, and the relationship between the maximum magnetic flux density and the current is Bmax= 0.5 I (mT). Figure 4 The maximum magnetic flux density occurs at time t = 0.5 s and t = 1.5 s, and the relationship between the maximum magnetic flux density and the current is Bmax= 0.5 I (mT). The height, width and thickness of the middle section of the electromagnetic driving system are designed to optimize the effective electromagnetic flux by keeping the magnetic core and the closed loop support iron column unsaturated, and by the limitation of the weight and overall size and the shape of the working space.

[0071] In one embodiment, the enhanced gradient magnetic field or rotating magnetic field of the electromagnetic driving system is used to deliver drugs. In another embodiment, such as drug diffusion in the treatment of osteoarthritis (OA), platelet-rich plasma (PRP) or other drugs loaded on the magnetic robot are directly injected into the joint cavity through a syringe. After injection, the drug must be evenly dispersed in the joint cavity to ensure the effective treatment of the drug, so the gradient magnetic field for dispersion is the key in this application. The viscosity in the inflamed joint is as high as 20 cp or higher, and since the blood viscosity is between 3.5 cp and 5.5 cp, the required gradient is much higher than most of the currently available gradient magnetic fields applied to blood vessel cavities. In order to implement such an application, the designed magnetic bridge has a height of 430 mm, a thickness of 25 mm, a width of 40 mm, a middle section length of 215 mm, and a second and third section length of 150 mm. The cone tip radius of the conical head is 3.5 mm, and the conical height is 40 mm. The core radius in the first and second electromagnetic devices is 25 mm, and the electromagnetic coil radius is 53 mm. The length of the core and the electromagnetic coil is 110 mm. The number of turns of the copper coil of the electromagnetic coil is 566 turns, and the cross-sectional ellipse of the copper wire is 1.6 mm x 3 mm. The resistance of a single electromagnetic device is 0.7 ohms, and the inductance is 13.7 mH. The overall weight is less than 70 kg. The rated working current of the electromagnetic device when working is 10 A, and the maximum current is 20 A. In the rated current dispersion magnetic working mode, the gradient at the center of the working space can reach 16 T / m. The minimum working space is a 40 mm sphere, and the commonly used working space is a 100 mm sphere. The working space can be further expanded according to the modular base design. Both the large base and the lower base in the base are preferably provided with multiple holes, and the working space is further expanded by moving the four pairs of magnetic bridges along the hole positions.

[0072] As can be seen from the above, the electromagnetic driving system as a whole uses less material than the materials of the prior art, requires less physical space, but the performance remains at a high level.

[0073] As can be seen from the above, the electromagnetic driving system as a whole uses less material than the materials of the prior art, requires less physical space, but the performance remains at a high level.

[0074] ​​In another embodiment, an extension rod is arranged between the conical head and the center of the iron core. Although the extension rod makes the whole space smaller, the magnetic field gradient of the whole system is further improved. This modular mechanical design makes the whole system more suitable for applications that require stronger gradients and smaller spaces. When the length of the extension rod is 30 mm, the horizontal and vertical gradients can reach 8.55 T / m and 9.7 T / m, respectively.

[0075] In summary, the electromagnetic driving system proposed in the present disclosure adopts a modular design and multiple magnetic field enhancement and driving methods, which can enhance the flexibility and scalability of clinical research and application. Compared with the existing method of changing the size of the space by using electromechanical systems, the purely mechanical design improves the safety of the electromagnetic driving system.

[0076] Although the embodiments of the present disclosure are described above in combination with the drawings, the present disclosure is not limited to the specific embodiments and application fields described above, and the specific embodiments described above are only illustrative and instructive, but not limiting. Those skilled in the art can make many forms under the guidance of the present disclosure and without departing from the scope protected by the claims of the present disclosure, which all belong to the protection of the present disclosure.

Claims

1. An electromagnetic drive system, characterized by, The system comprises four closed-loop magnetic bridges, each of which is connected with a first electromagnetic device and a second electromagnetic device; The first electromagnetic device and the second electromagnetic device are identical, each comprising a conical head, a first anti-magnetic dissipation device, an iron core, an electromagnetic coil and a second anti-magnetic dissipation device, wherein the radius of the tip of the conical head is greater than zero, the bottom of the conical head is fixed with the first end of the iron core, the iron core is located in the electromagnetic coil, and the first anti-magnetic dissipation device is clamped between the conical head and the electromagnetic coil; the second end of the iron core is fixed with the second segment or the fourth segment of the magnetic bridge, and the second anti-magnetic dissipation device is clamped between the electromagnetic coil and the magnetic bridge; The size of the working space is adjusted and the gradient of the magnetic field is enhanced by an extension rod between the center of the conical head and the iron core, the shortest length of the extension rod is determined by the minimum length of the end of the fixed conical head, and the longest length is determined by the minimum working space; The magnetic bridge comprises a first segment, a second segment, an intermediate segment, a third segment and a fourth segment connected in sequence, the first segment and the fourth segment are parallel, the second segment and the third segment are equal in length, and the second segment and the third segment form an angle with the intermediate segment, the first electromagnetic device is connected to the second segment, and the second electromagnetic device is connected to the third segment; the gradient magnetic field in the vertical direction is enhanced by the first segment and the fourth segment.

2. The electromagnetic drive system of claim 1, wherein, The magnetic bridge is installed on a base, the base has holes capable of adjusting the installation position, and the working space can be increased by moving the four groups of magnetic bridges outward at the same time.

3. The electromagnetic drive system of claim 1, wherein, The length of the extension rod is 20-30 mm.

4. The electromagnetic drive system of claim 1, wherein, The weight of the electromagnetic driving system is less than 70 kg, and the height is less than 500 mm.

5. An electromagnetic device, characterized in that: The electromagnetic device comprises a conical head, a first anti-magnetic dissipation device, an iron core, an electromagnetic coil and a second anti-magnetic dissipation device, wherein the radius of the tip of the conical head is greater than zero, the bottom of the conical head is fixed with the first end of the iron core, the iron core is located in the electromagnetic coil, and the first anti-magnetic dissipation device is clamped between the conical head and the electromagnetic coil; the second end of the iron core is fixed with the second segment or the fourth segment of the magnetic bridge, and the second anti-magnetic dissipation device is clamped between the electromagnetic coil and the magnetic bridge; The size of the working space is adjusted and the gradient of the magnetic field is enhanced by an extension rod between the center of the conical head and the iron core, the shortest length of the extension rod is determined by the minimum length of the end of the fixed conical head, and the longest length is determined by the minimum working space; The magnetic bridge comprises a first segment, a second segment, an intermediate segment, a third segment and a fourth segment connected in sequence, the first segment and the fourth segment are parallel, the second segment and the third segment are equal in length, and the second segment and the third segment form an angle with the intermediate segment, the first electromagnetic device is connected to the second segment, and the second electromagnetic device is connected to the third segment; the gradient magnetic field in the vertical direction is enhanced by the first segment and the fourth segment.

6. A method for generating a magnetic field in a workspace of an electromagnetic drive system, the electromagnetic drive system comprising four closed-loop magnetic bridges, each magnetic bridge being connected with a first electromagnetic device and a second electromagnetic device, the first electromagnetic device and the second electromagnetic device being identical and each comprising a conical head, a first magnetic dispersion-preventing device, an iron core, an electromagnetic coil, and a second magnetic dispersion-preventing device, wherein: the first magnetic dispersion-preventing device is arranged between the conical head and the iron core, the second magnetic dispersion-preventing device is arranged between the iron core and the electromagnetic coil, the first magnetic dispersion-preventing device and the second magnetic dispersion-preventing device are arranged in a same plane, and the first magnetic dispersion-preventing device and the second magnetic dispersion-preventing device are arranged symmetrically with respect to a central axis of the electromagnetic device. The magnetic bridge comprises a first segment, a second segment, an intermediate segment, a third segment and a fourth segment connected in sequence, the first segment and the fourth segment are parallel, the second segment and the third segment are equal in length, and the second segment and the third segment form an included angle with the intermediate segment, a first electromagnetic device is connected to the second segment, and a second electromagnetic device is connected to the third segment; the first segment and the fourth segment ensure the enhanced gradient magnetic field in the vertical direction; the tip radius of the conical head is greater than zero, the bottom of the cone is fixed to the first end of the iron core, the iron core is located in the electromagnetic coil, and the first magnetic dispersion prevention device is clamped between the conical head and the electromagnetic coil; the second end of the iron core and the second segment or the fourth segment of the magnetic bridge are fixed, and the second magnetic dispersion prevention device is clamped between the electromagnetic coil and the magnetic bridge; the size of the working space is adjusted and the gradient of the magnetic field is enhanced by the extension rod between the conical head and the center of the iron core, and the shortest length of the extension rod is determined by the minimum length of the end of the fixed conical head, and the longest length is determined by the minimum working space; the method comprises: By working the first electromagnetic device and / or the second electromagnetic device at a preset position, a preset magnetic field mode is generated, and the magnetic field mode comprises an enhanced gradient magnetic field, a uniform magnetic field, a rotating magnetic field, an oscillating magnetic field and a dispersed gradient magnetic field.

7. The method of claim 6, wherein, The method comprises: By driving a pair of electromagnetic devices on one magnetic bridge in opposite directions to generate a magnetic loop, a horizontal direction enhanced gradient magnetic field is generated; four electromagnetic devices in the upper half or the lower half are divided into two groups, two adjacent electromagnetic devices are taken as one group, and by driving the two groups of electromagnetic devices, the current direction of one group of electromagnetic devices is opposite to that of the other group, so as to generate a vertical direction enhanced gradient magnetic field; By configuring two electromagnetic devices meeting a preset distance to work to generate a uniform magnetic field, the two electromagnetic devices meeting the preset distance are two electromagnetic devices located on the second segment and the third / second segment of the opposite magnetic bridge, or two electromagnetic devices located on the second segment and the third segment of the adjacent magnetic bridge; By driving four preset electromagnetic devices to work in time, the rotating magnetic field is generated, the four preset electromagnetic devices are the electromagnetic devices on the second segment of each magnetic bridge, or the electromagnetic devices on the third segment of each magnetic bridge, or four electromagnetic devices on the opposite magnetic bridge, or four electromagnetic devices on the adjacent two magnetic bridges; The oscillating magnetic field is generated by making preset working currents of four electromagnetic devices satisfy the following excitation functions respectively: , , and wherein, is the current amplitude, a constant parameter, , is the oscillation frequency, is the time, the oscillation angle , the oscillation angle can be changed by adjusting the constant parameter ; the preset four electromagnetic devices are four electromagnetic devices of the second segment of each magnetic bridge, or four electromagnetic devices of the third segment of each magnetic bridge, or four electromagnetic devices on the opposite two magnetic bridges, or four electromagnetic devices on the adjacent two magnetic bridges. By driving two pairs of electromagnetic devices on the opposite magnetic bridge, the direction of the magnetic loop generated by one pair of electromagnetic devices is opposite to that of the other pair, so as to generate the dispersed gradient magnetic field; or two pairs of adjacent four electromagnetic devices are divided into a group, and by driving the two groups of electromagnetic devices, the direction of the magnetic loop formed by the two pairs of electromagnetic devices in one group is opposite to that of the other group, so as to generate the dispersed gradient magnetic field.

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