A micro-nano satellite electromagnetic docking mechanism and its design method

Abstract

The present invention belongs to the technical field of satellite docking equipment and discloses a micro-nano satellite electromagnetic docking mechanism, including an active docking component and a passive docking component. The active docking component includes a head shell, a head connector, an electromagnet cylinder, a locking component and a positioning cone. The locking component includes a screw, a locking motor and a latch. The screw is connected between the bearing of the head shell and the locking motor. The screw is provided with forward and reverse threads, and forward and reverse conical nuts are threadedly connected to the forward and reverse threads. A tension spring is connected between the two latches. The passive docking component includes an electromagnet, a docking limit tooth and a docking guide cylinder. The limit tooth is connected to the iron core of the electromagnet, the upper inclined surface of the docking limit tooth is consistent with the docking guide cylinder, and the lower inclined surface of the docking limit tooth has the same inclination angle as the latch. The present invention solves the problems of fuel consumption, plume pollution, docking impact and the like in existing mainstream docking methods, and is suitable for scenarios such as the free docking combination of multiple micro-nano satellites and the configuration transformation of the combination.

Description

Technical Field

[0001] The present invention relates to the technical field of satellite docking equipment, and in particular to a micro-nano satellite electromagnetic docking mechanism and a design method thereof. Background Art

[0002] In recent years, the diversity of space missions has continued to increase, leading to a surge in demand for on-orbit assembly, replacement, expansion, and upgrades of spacecraft. Micro-nano satellite on-orbit docking and configuration-shifting technology, with its scalable functionality, reusability, and low launch costs, has become a mainstream technology development. As a key component, the space docking mechanism plays a vital role in the docking, locking, and separation of spacecraft during space missions.

[0003] Traditional spacecraft connection technologies mostly rely on thrusters that generate reaction force through jets. Space electromagnetic docking offers advantages over traditional docking technologies, including no fuel consumption, no plume contamination, and easily controlled docking impacts. Electromagnetic docking technology will address the need for repeated docking of micro- and nanosatellites, avoiding failure of docking conformational function due to propellant depletion and extending their operational lifespan. The continuous and stable non-contact force it provides can theoretically control docking contact velocity to zero, preventing instrument damage from docking collisions and enabling flexible docking.

[0004] Since the concept of space electromagnetic docking was first proposed in 2000, several projects have been conducting related research, including the OASIS (On Orbit Autonomous Servicing Satellite) project at the University of Washington, the MiniAERCam (Miniature Autonomous Extravehicular Robotic Camera) project at NASA's Johnson Space Center, the EGADS (Electromagnetically Guided Autonomous Docking and Separation in Microgravity) project at the University of Texas, the ISMs (Intelligent Self-powered Modules) project at the University of Surrey, and the AAReST (Autonomous Assembly of a Reconfigurable Space Telescope) project. Most of these projects use electromagnetic interactions generated by one or more electromagnetic coils to achieve functions such as connecting, separating, releasing, and recovering satellites. Currently, most electromagnetic docking technology research focuses on electromagnetic control, with few projects or reports specifically addressing core components such as electromagnetic coils. Summary of the Invention

[0005] The present invention aims to provide a micro-nano satellite electromagnetic docking mechanism and a design method thereof to solve the problem that existing research on spacecraft electromagnetic docking technology is mostly based on the control level and lacks analysis and research on core electromagnetic docking components such as electromagnetic coils.

[0006] In order to achieve the above object, the present invention provides a technical solution as follows:

[0007] A micro-nano satellite electromagnetic docking mechanism includes an active docking component installed on a primary satellite and a passive docking component installed on a secondary satellite.

[0008] The active docking assembly includes a bowl-shaped head shell, two head connectors, an electromagnet cylinder, a locking assembly, and a positioning round table, which are arranged in sequence from left to right. The same position of the outer wall of the head shell, the head connector, and the positioning round table is provided with a boss, and each two of the bosses are connected by a screw. A through hole is provided in the center of the side wall of the head shell, and the through hole is used to install the bearing of the screw to be installed;

[0009] The maximum diameter of each head connecting piece close to the head connecting piece is smaller than the maximum diameter of the head shell, and the two head connecting pieces are connected between the head shell and the positioning frustum;

[0010] The positioning cone is composed of two symmetrically arranged semi-conical structures, and a cavity is commonly provided in the two semi-conical structures;

[0011] The electromagnet cylinder is connected to the positioning stage, an electromagnet is provided inside the electromagnet cylinder, the electromagnet cylinder and the satellite are interference fit through a bearing, and the electromagnet cylinder is bolted to the rear end cover;

[0012] The locking assembly includes a screw rod, a locking motor and a latch, the screw rod is connected between the bearing of the head shell and the locking motor, the screw rod is provided with forward and reverse threads with opposite rotation directions respectively located in the cavities of the head shell and the positioning round table, the forward and reverse threads are threadedly connected with forward and reverse conical nuts slidably connected to the inner wall of the head shell and forward and reverse conical nuts slidably connected to the inner cavity of the positioning round table, the locking motor is installed on the rear end cover of the electromagnet cylinder, the latch is T-shaped, and two wedge surfaces of two forward and reverse conical nuts are respectively provided at both ends of the latch, and the other end of the latch is located in the gap enclosed by the two head connecting parts, and the size of the other end of the latch is smaller than the size of the space enclosed by the two head connecting parts, the two latches are respectively slidably connected to the two head connecting parts, and a tension spring is connected between the two latches;

[0013] The passive docking assembly includes an electromagnet, a docking limit tooth threadedly connected to the iron core of the electromagnet, and a docking guide cylinder threadedly connected to the iron core of the electromagnet, and the size of the docking guide cylinder is consistent with the positioning round table;

[0014] There are a total of 10 docking limit teeth, which are connected to the iron core of the electromagnet through threads. The upper inclined surface of the docking limit teeth is consistent with the docking guide cylinder, and the lower inclined surface of the docking limit teeth has the same inclination angle as the pin.

[0015] Preferably, the rotating assembly includes a rotating motor, a worm gear and a worm connected to the worm gear, the rotating motor is mounted on the inner surface of the satellite, the worm gear is mounted on the electromagnet cylinder, and the worm is connected to the rotating motor.

[0016] Another technical solution provided by the present invention is as follows:

[0017] The design method of the docking mechanism comprises the following steps:

[0018] Step 1: Determine the design parameters based on the project requirements:

[0019] Determine the range of micro-nano satellite docking and the magnitude of the electromagnetic force required, or determine the inter-satellite relative acceleration based on the satellite mass and docking time, and calculate the required electromagnetic force accordingly;

[0020] Give the size requirements of the electromagnetic docking mechanism, or obtain the size requirements of the electromagnet based on the quality requirements of the electromagnetic docking mechanism:

[0021]

[0022] Step 2: Provide a far-field model of intersatellite electromagnetic force based on the magnetic dipole hypothesis. Perform a preliminary design based on the far-field model and project requirements and provide initial parameters:

[0023] For the two coils A and B in space, calculate the interaction force and torque between them;

[0024] Assume that the relative vector between a point in space and the current element in coil A is r. Applying the Biot-Savart theorem, we can obtain the magnetic field strength of all current elements in coil A at this point:

[0025]

[0026] Where μ0 = 4π × 10 -7 N / A 2 is the vacuum permeability, i A is the current intensity of coil A, dl A is the vector element of coil A along the direction of current;

[0027] Remember i B is the current intensity of coil B, then any vector element dl on coil B B In B AThe Ampere force and moment under action are:

[0028] dF B =i B dl B ×B A

[0029] dτ B =R B ×dF B

[0030] Combining the two equations and integrating them, we can get the electromagnetic force and torque of coil A on coil B:

[0031]

[0032]

[0033] Let s be the relative vector from the center of the coil to a point in space, then:

[0034] r=sR

[0035] Since it is a far-field model, R<<s, and both coils are regarded as magnetic dipoles, their magnetic moments are:

[0036] μ=iSe z

[0037] Where i is the total current of the coil, S is the area of the coil, and e z is the normal unit vector to the coil axis;

[0038] Since the above electromagnetic force and torque model is non-analytical, Taylor expansion is used for approximation. Let the vector connecting the centers of coils A and B be d. Then the magnetic induction intensity generated by coil A in the far field is:

[0039]

[0040] Then the electromagnetic force and torque on the energized coil B in the magnetic field of the energized coil A are:

[0041]

[0042] τ B =μ B ×B A

[0043] After substituting, we can get the electromagnetic force of the two energized coils and the far-field model of the electromagnetic coil:

[0044]

[0045]

[0046]

[0047]

[0048] After determining the size of the electromagnet according to the design requirements, the required current and number of turns can be estimated based on the far-field model. When the axes of the two coils coincide, the above formula is simplified to:

[0049]

[0050] Jointly:

[0051]

[0052] Define the current turns density J A 、J B Represents the current flowing through the coil per unit length and per unit thickness. This value is a constant, 3A / mm 2 ;

[0053] Therefore, the current i A 、i B Decomposed into length l A 、l B , winding thickness h A 、h B and current turns density J A 、J B The product of:

[0054]

[0055] Since the theoretical calculation does not consider the iron core, let h = r, that is, there is no iron core, and the electromagnet is composed entirely of coils, and the above formula becomes:

[0056]

[0057] Substitute the target distance and required electromagnetic force into the above formula to calculate the size design parameter range of electromagnets A and B. Combined with the size requirements obtained in step 1, the electromagnets can be preliminarily designed.

[0058] Step 3: Based on the basic principles of electromagnetic fields, an accurate model of electromagnetic force expressed in integral form is given for numerical simulation to improve the design parameters;

[0059] The space docking electromagnet is analyzed through numerical simulation. Ansoft Maxwell is used to establish a model and perform numerical calculations of electromagnetic force. The numerical simulation is based on the precise model of electromagnetic force expressed in integral form:

[0060]

[0061] According to the electromagnetic force values obtained by simulation, the design parameters are adjusted within the condition range to obtain the optimized and improved design parameters;

[0062] Step 4: Conduct dynamic analysis of the docking process of the electromagnetic docking mechanism and determine the control strategy;

[0063] Adams and Maxwell were used to simulate the dynamic process of the electromagnetic docking mechanism. The electromagnetic force variation curve and the corresponding coil current value that met the conditions under different initial conditions were calculated to control the relative speed and acceleration of the entire docking process.

[0064] Step five: Make a prototype of the docking mechanism and conduct experiments to verify the electromagnetic force and feasibility of the solution.

[0065] Beneficial effects of the present invention:

[0066] 1. This solution has the advantages of small size, light weight, and reusability, which are in line with the application characteristics of micro-nano satellites.

[0067] 2. This scheme adopts the electromagnetic docking method, which has the advantages of no propellant consumption and no plume pollution, and can theoretically achieve collision-free docking. The electromagnetic torque can achieve autonomous correction under certain initial position and attitude deviation. BRIEF DESCRIPTION OF THE DRAWINGS

[0068] Figure 1 This is a cross-sectional view of an active docking mechanism in a micro-nano satellite electromagnetic docking mechanism of the present invention;

[0069] Figure 2 This is a front view of an active docking mechanism in a micro-nano satellite electromagnetic docking mechanism of the present invention;

[0070] Figure 3 This is an exploded view of the interior of an active docking mechanism in a micro-nano satellite electromagnetic docking mechanism of the present invention;

[0071] Figure 4 The figure is a cross-sectional view of a passive docking mechanism in a micro-nano satellite electromagnetic docking mechanism according to the present invention. DETAILED DESCRIPTION

[0072] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments:

[0073] The figure marks in the drawings of the specification include: head shell 1, head connecting part 2, positioning cone 3, electromagnet cylinder 4, limit bar 5, limit block 6, screw 7, locking motor 8, pin 9, forward and reverse conical nut 10, second limit groove 11, docking limit tooth 12, rotating motor 13, and worm gear 14.

[0074] like Figure 1-4As shown, a micro-nano satellite electromagnetic docking mechanism includes an active docking component installed on a primary satellite and a passive docking component installed on a secondary satellite.

[0075] The active docking assembly includes, from left to right, a bowl-shaped head housing 1, two head connectors 2, an electromagnet cylinder 4, a locking assembly, and a positioning platform 3. Bosses are located at the same points on the outer walls of the head housing 1, the head connectors 2, and the positioning platform 3, and each pair of bosses is connected by screws. A through-hole is provided in the center of the side wall of the head housing 1, housing a bearing for a screw rod 7. A first limiting groove and a limiting bar 5 are also symmetrically arranged within the head housing 1. The two limiting grooves and two limiting bars 5 are distributed in a cross pattern within the head connector 2.

[0076] Each head connector 2 has an integrally formed limit block 6 on one side away from the center. The two limit blocks 6 slide into their corresponding first limit slots. The maximum diameter of each head connector 2 is smaller than the maximum diameter of the head housing 1. The two head connectors 2 are connected between the head housing 1 and the positioning platform 3, each bolted to the positioning platform 3. The two head connectors 2, the head housing 1, and the positioning platform 3 enclose two symmetrically distributed rectangular openings.

[0077] The positioning cone 3 is composed of two symmetrically arranged semi-conical structures. A cavity is commonly defined in the two semi-conical structures, and limiting strips 5 are symmetrically arranged in the cavity.

[0078] The electromagnet cylinder 4 is connected to the positioning stage 3 by screws. An electromagnet is provided inside the electromagnet cylinder 4. The electromagnet cylinder 4 and the main satellite are interference fit through bearings. The electromagnet cylinder 4 is bolted to the rear end cover.

[0079] The locking assembly includes a screw rod 7, a locking motor 8 and a pin 9. The screw rod 7 is connected between the bearing of the head shell 1 and the locking motor 8. The screw rod 7 is provided with forward and reverse threads with opposite rotation directions, respectively located in the cavities of the head shell 1 and the positioning cone 3. The forward and reverse threads are threadedly connected with forward and reverse conical nuts 10 that are slidably connected to the inner wall of the head shell 1 and forward and reverse conical nuts 10 that are slidably connected to the cavity in the positioning cone 3. The two forward and reverse conical nuts 10 are symmetrically provided with second limiting grooves 11. The second limiting grooves 11 on each forward and reverse conical nut 10 are respectively slidably connected to the limiting bar 5 in the cavity on the head shell 1 or the positioning cone 3. The locking motor 8 is installed on the rear end cover of the electromagnet cylinder 4. The pin 9 is T-shaped. Two wedge surfaces that conflict with each other at both ends of the pin 9 are respectively provided. The other end of the pin 9 is located in the gap enclosed by the two head connectors 2, and the size of the other end of the pin 9 is smaller than the size of the space enclosed by the two head connectors 2. The two pins 9 are respectively slidably connected to the two head connectors 2, and a tension spring is connected between the two pins 9.

[0080] The passive docking assembly includes an electromagnet, a docking limit tooth 12 threadedly connected to the iron core of the electromagnet, and a docking guide cylinder threadedly connected to the iron core of the electromagnet. The size of the docking guide cylinder is consistent with that of the positioning cone 3.

[0081] There are a total of 10 docking limit teeth 12, which are connected to the iron core of the electromagnet through integral molding. The upper inclined surface of the docking limit teeth 12 is consistent with the docking guide cylinder, and the lower inclined surface of the docking limit teeth 12 has the same inclination angle as the pin 9.

[0082] The rotating assembly includes a rotating motor 13 , a worm gear 14 and a worm connected to the worm gear 14 . The rotating motor 13 is mounted on the inner surface of the satellite, the worm gear 14 is mounted on the electromagnet cylinder 4 , and the worm is connected to the rotating motor 13 .

[0083] The docking method of this solution includes the following steps:

[0084] 1.1) Using navigation guidance and orbit control, the two satellites are brought close together within the electromagnetic force range to achieve preliminary alignment.

[0085] 1.2) Once within the electromagnetic force range, the two electromagnets are energized, causing them to attract each other. By changing the direction and magnitude of the current, the electromagnetic force is precisely controlled, thereby controlling the relative speed of the docking process.

[0086] 1.3) Under the guidance of the guide cone and the docking guide cylinder, the active docking part and the passive docking part are combined, and the outer wall boss of the head shell 1 is guided to a fixed position by the docking limit teeth 12, limiting the axial rotation of the two satellites;

[0087] 1.4) The controller controls the docking locking device to operate. The locking motor 8 drives the screw 7 to rotate, and the forward and reverse conical nuts 10 move toward each other, causing the latch 9 to extend and fit with the lower inclined surface of the docking limit tooth 12, thus locking the two mechanisms.

[0088] 1.5) The active electromagnet and the passive electromagnet are powered off, completing the docking process.

[0089] The rotation method of this scheme includes the following steps:

[0090] 2.1) The controller sends a rotation command to the rotating motor;

[0091] 2.2) The rotating motor generates driving force, which is driven by the worm gear, and the torque is transmitted by the outer wall boss of the head shell 1 and the docking limit teeth 12, driving the relative angle of the primary and secondary satellites to change.

[0092] The release method of this solution includes the following steps:

[0093] 3.1) The controller controls the docking locking device to operate. The locking motor 8 drives the screw 7 to rotate, and the forward and reverse conical nuts 10 move in opposite directions. The latch 9 is retracted into the housing under the action of the tension spring, and the two mechanisms are unlocked.

[0094] 3.2) The active and passive electromagnets are energized to repel each other, causing the two satellites to gradually separate.

[0095] 3.3) The active electromagnet and the passive electromagnet are powered off, completing the release process.

[0096] The design method of the electromagnetic docking mechanism includes the following steps:

[0097] Step 1: Determine the design parameters based on the project requirements:

[0098] Determine the range of micro-nano satellite docking and the magnitude of the electromagnetic force required, or determine the inter-satellite relative acceleration based on the satellite mass and docking time, and calculate the required electromagnetic force accordingly;

[0099] Give the size requirements of the electromagnetic docking mechanism, or obtain the size requirements of the electromagnet based on the quality requirements of the mechanism:

[0100]

[0101] Step 2: Provide a far-field model of intersatellite electromagnetic force based on the magnetic dipole hypothesis. Perform a preliminary design based on the far-field model and project requirements and provide initial parameters:

[0102] For the two coils A and B in space, calculate the interaction force and torque between them.

[0103] Assume that the relative vector between a point in space and the current element in coil A is r. Applying the Biot-Savart theorem, we can obtain the magnetic field strength of all current elements in coil A at this point:

[0104]

[0105] Where μ0 = 4π × 10 -7 N / A 2 is the vacuum permeability, i A is the current intensity of coil A, dl A is the vector element of coil A along the direction of current;

[0106] Remember i B is the current intensity of coil B, then any vector element dl on coil B B In R A The Ampere force and moment under action are:

[0107] dF B =i B dlB ×B A

[0108] dτ B =R B ×dF B

[0109] Combining the two equations and integrating them, we can get the electromagnetic force and torque of coil A on coil B:

[0110]

[0111]

[0112] Let s be the relative vector from the center of the coil to a point in space, then:

[0113] r=sR

[0114] Since it is a far-field model, R<<s, and both coils are regarded as magnetic dipoles, their magnetic moments are:

[0115] μ=iSe z

[0116] Where i is the total current of the coil, S is the area of the coil, and e z is the unit vector normal to the coil axis.

[0117] Since the above electromagnetic force and torque model is non-analytical, Taylor expansion is used for approximation. Let the vector connecting the centers of coils A and B be d. Then the magnetic induction intensity generated by coil A in the far field is:

[0118]

[0119] Then the electromagnetic force and torque on the energized coil B in the magnetic field of the energized coil A are:

[0120]

[0121] τ B =μ B ×B A

[0122] After substituting, we can get the electromagnetic force of the two energized coils and the far-field model of the electromagnetic coil:

[0123]

[0124]

[0125]

[0126]

[0127] After determining the size of the electromagnet according to the design requirements, the required current and number of turns can be estimated based on the far-field model. When the axes of the two coils coincide, the above formula is simplified to:

[0128]

[0129] Jointly:

[0130]

[0131] Define the current turns density J A 、J B Represents the current flowing through the coil per unit length and per unit thickness. This value is a constant, approximately 3A / mm 2 , that is, when the relative position and distance between the two coils are constant, the magnitude of the electromagnetic force is only related to the coil radius, length and winding thickness.

[0132] Therefore, the current i A 、i B Decomposed into length l A 、l B , winding thickness h A 、h B and current turns density J A 、J B The product of:

[0133]

[0134] Since the theoretical calculation does not consider the iron core, let h = r, that is, there is no iron core, and the electromagnet is composed entirely of coils, and the above formula becomes:

[0135]

[0136] Substitute the target distance and required electromagnetic force into the above formula to calculate the size design parameter range of electromagnets A and B. Combined with the size requirements obtained in step 1, the electromagnets can be preliminarily designed.

[0137] Step three: Based on the basic principles of electromagnetic fields, an accurate model of electromagnetic force expressed in integral form is given for numerical simulation to improve the design parameters.

[0138] Due to the complexity of the actual situation, theoretical derivation cannot quantitatively consider aspects such as the iron core and magnetic loss. Therefore, numerical simulation methods are further used to analyze the space docking electromagnet. Ansoft Maxwell is used to establish a model and perform numerical calculations of the electromagnetic force. The numerical simulation is based on the precise model of the electromagnetic force expressed in integral form:

[0139]

[0140] According to the electromagnetic force values obtained by simulation, the design parameters are adjusted within the condition range to obtain the optimized and improved design parameters.

[0141] Step 4: Conduct dynamic analysis of the docking process of the electromagnetic docking mechanism and determine the control strategy.

[0142] Adams and Maxwell were used to jointly simulate the docking dynamics process of the electromagnetic docking mechanism. The electromagnetic force variation curve and the corresponding coil current value that met the conditions under different initial conditions were calculated to control the relative speed and acceleration of the entire docking process.

[0143] Step five: Make a prototype of the docking mechanism and conduct experiments to verify the electromagnetic force and feasibility of the solution.

[0144] The above is only an embodiment of the present invention, and common knowledge such as specific technical solutions or characteristics in the implementation scheme is not described in detail here. It should be pointed out that for those skilled in the art, without departing from the technical solution of the present invention, several variations and improvements can be made, which should also be regarded as the scope of protection of the present invention, and these will not affect the effect of the implementation of the present invention and the practicality of the patent. The scope of protection required by this application shall be based on the content of its claims, and the specific implementation methods and other records in the description can be used to interpret the content of the claims.

Claims

1. A micro-nano satellite electromagnetic docking mechanism, characterized by: It includes an active docking assembly installed on the primary satellite and a passive docking assembly installed on the secondary satellite. The active docking assembly comprises a bowl-shaped head shell (1), two head connectors (2), an electromagnet cylinder (4), a locking assembly and a positioning truncated table (3) which are arranged in sequence from left to right. Bosses are provided at the same locations on the outer walls of the head shell (1), the head connector (2) and the positioning truncated table (3). Every two bosses are connected by screws. A through hole is provided at the center of the side wall of the head shell (1). The through hole is used to install a bearing for a screw rod (7) to be installed. The maximum diameter of each head connecting piece (2) on the side close to the head connecting piece is smaller than the maximum diameter of the head shell (1), and the two head connecting pieces (2) are connected between the head shell (1) and the positioning frustum (3); The positioning cone (3) is composed of two symmetrically arranged semi-conical structures, and a cavity is commonly provided in the two semi-conical structures; The electromagnet cylinder (4) is connected to the positioning truncated table (3), an electromagnet is provided inside the electromagnet cylinder (4), the electromagnet cylinder (4) and the satellite are interference-fitted via a bearing, and the electromagnet cylinder (4) is bolted to a rear end cover; The locking assembly comprises a screw (7), a locking motor (8) and a latch (9), wherein the screw (7) is connected between the bearing of the head shell (1) and the locking motor (8), and the screw (7) is provided with forward and reverse threads respectively located in the cavities of the head shell (1) and the positioning truncated cone (3), wherein the forward and reverse threads are both threadedly connected with forward and reverse conical nuts (10) which are slidably connected to the inner wall of the head shell (1) and the forward and reverse conical nuts (10) which are slidably connected to the inner cavity of the positioning truncated cone (3). The machine (8) is installed on the rear end cover of the electromagnet cylinder (4), the latch (9) is T-shaped, and two wedge surfaces are provided at both ends of the latch (9) for contacting with two conical nuts (10) with opposite directions. The other end of the latch (9) is located in the gap enclosed by the two head connectors (2), and the size of the other end of the latch (9) is smaller than the size of the space enclosed by the two head connectors (2). The two latches (9) are respectively slidably connected to the two head connectors (2), and a tension spring is connected between the two latches (9); The passive docking assembly comprises an electromagnet, a docking limit tooth (12) threadedly connected to the iron core of the electromagnet, and a docking guide cylinder threadedly connected to the iron core of the electromagnet, wherein the size of the docking guide cylinder is engaged with the positioning truncated cone (3); There are a total of 10 docking limit teeth (12), which are connected to the iron core of the electromagnet through threads, and the upper inclined surface of the docking limit teeth (12) is consistent with the docking guide cylinder, and the lower inclined surface of the docking limit teeth (12) has the same inclination angle as the latch (9).

2. The micro-nano satellite electromagnetic docking mechanism according to claim 1, characterized in that: The invention also includes a rotating assembly, which includes a rotating motor (13), a worm gear (14) and a worm connected to the worm gear (14). The rotating motor (13) is installed on the inner surface of the satellite, the worm gear (14) is installed on the electromagnet cylinder (4), and the worm is connected to the rotating motor (13).

3. A micro-nano satellite electromagnetic docking mechanism according to any one of claims 1-2, characterized in that: The design method of the docking mechanism comprises the following steps: Step 1: Determine the design parameters based on the project requirements: Determine the range of micro-nano satellite docking and the magnitude of the electromagnetic force required, or determine the inter-satellite relative acceleration based on the satellite mass and docking time, and calculate the required electromagnetic force accordingly; Give the size requirements of the electromagnetic docking mechanism, or obtain the size requirements of the electromagnet based on the quality requirements of the electromagnetic docking mechanism: Step 2: Provide a far-field model of intersatellite electromagnetic force based on the magnetic dipole hypothesis. Perform a preliminary design based on the far-field model and project requirements and provide initial parameters: For the two coils A and B in space, calculate the interaction force and torque between them; Assume that the relative vector between a point in space and the current element in coil A is r. Applying the Biot-Savart theorem, we can obtain the magnetic field strength of all current elements in coil A at this point: Where μ0 = 4π × 10 -7 N / A 2 is the vacuum permeability, i A is the current intensity of coil A, dl A is the vector element of coil A along the direction of current; Remember i B is the current intensity of coil B, then any vector element dl on coil B B In B A The Ampere force and moment under action are: dF B =i B dl B ×B A dτ B =R B ×dF B Combining the two equations and integrating them, we can get the electromagnetic force and torque of coil A on coil B: Let s be the relative vector from the center of the coil to a point in space, then: r=sR Since it is a far-field model, R<<s, and both coils are regarded as magnetic dipoles, their magnetic moments are: μ=iSe z Where i is the total current of the coil, S is the area of the coil, and e z is the normal unit vector to the coil axis; Since the above electromagnetic force and torque model is non-analytical, Taylor expansion is used for approximation. Let the vector connecting the centers of coils A and B be d. Then the magnetic induction intensity generated by coil A in the far field is: Then the electromagnetic force and torque on the energized coil B in the magnetic field of the energized coil A are: t B =μ B ×B A After substituting, we can get the electromagnetic force of the two energized coils and the far-field model of the electromagnetic coil: After the electromagnet size is determined according to the design requirements, the required current and number of turns can be estimated based on the far-field model. When the axes of the two coils coincide, the above formula can be simplified to: Jointly: Define the current turns density J A 、J B Represents the current flowing through the coil per unit length and per unit thickness. This value is a constant, 3A / mm 2 ; Therefore, the current i A 、i B Decomposed into length l A 、l B , winding thickness h A 、h B and current turns density J A 、J B The product of: Since the theoretical calculation does not consider the iron core, let h = r, that is, there is no iron core, and the electromagnet is composed entirely of coils, and the above formula becomes: Substitute the target distance and required electromagnetic force into the above formula to calculate the size design parameter range of electromagnets A and B. Combined with the size requirements obtained in step 1, the electromagnets can be preliminarily designed. Step 3: Based on the basic principles of electromagnetic fields, an accurate model of electromagnetic force expressed in integral form is given for numerical simulation to improve the design parameters; The space docking electromagnet is analyzed through numerical simulation. Ansoft Maxwell is used to establish a model and perform numerical calculations of electromagnetic force. The numerical simulation is based on the precise model of electromagnetic force expressed in integral form: According to the electromagnetic force values obtained by simulation, the design parameters are adjusted within the condition range to obtain the optimized and improved design parameters; Step 4: Conduct dynamic analysis of the docking process of the electromagnetic docking mechanism and determine the control strategy; Adams and Maxwell were used to simulate the dynamic process of the electromagnetic docking mechanism. The electromagnetic force variation curve and the corresponding coil current value that met the conditions under different initial conditions were calculated to control the relative speed and acceleration of the entire docking process. Step five: Make a prototype of the docking mechanism and conduct experiments to verify the electromagnetic force and feasibility of the solution.

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