Electromagnetic sleeve device and landing method for the final stage landing of a launch vehicle

Abstract

The application discloses an electromagnetic sleeve device and a landing method for the final stage landing of a carrier rocket. The electromagnetic sleeve device comprises an electromagnetic sleeve, a magnetic field source array installed on the inner wall of the electromagnetic sleeve and a magnetic element array installed on the outer wall of the rocket. The electromagnetic sleeve is an electrically conductive hollow cylinder with an open upper portion. The magnetic field source array and the magnetic element array respectively comprise multiple layers of axially arranged magnetic field sources and magnetic elements. Each layer comprises an even number of circumferentially fixed magnetic field sources and magnetic elements. The magnetic field sources and the magnetic elements are radially magnetized, and the adjacent magnetic field sources have opposite magnetic pole directions. The application realizes the lateral self-centering and eddy current deceleration of the rocket in a non-contact manner, has real-time self-adjusting and compensating capabilities, and can very accurately recycle the rocket to a central landing position. The response of the electromagnetic force is instantaneous, the recycling process of the rocket is short, and the efficiency is high. Direct physical contact between components is eliminated, the components are not worn, and the service life of the equipment is long.

Description

Technical Field

[0001] This application relates to the field of reusable launch vehicle recovery technology, and in particular to an electromagnetic sleeve device and landing method for the terminal landing of a launch vehicle. Background Technology

[0002] Reusable launch vehicles represent a crucial development direction for reducing the cost of space launches. After completing its mission, the rocket re-enters the atmosphere, undergoing aerodynamic deceleration, retro-rocket deceleration, and grid fin attitude control, ultimately making contact with the ground or landing site at a low speed in the terminal phase. This terminal landing process is the critical bottleneck for the reliability of the entire recovery mission; even slight deviations can lead to rocket tipping, damage, or recovery failure.

[0003] One of the commonly used terminal landing methods for reusable launch vehicles is vertical landing with outriggers. The rocket has foldable and deployable landing outriggers installed at the bottom. After the rocket decelerates to near zero speed during the terminal phase, the outriggers deploy and the rocket lands vertically on a land-based landing site or an unmanned barge at sea. This method relaxes the accuracy requirements, but the disadvantage is that the landing outriggers and their deployment mechanism account for a considerable proportion of the rocket's dry weight (usually 1.5 to 3 tons, accounting for 5% to 10% of the dry weight), which reduces the effective payload capacity.

[0004] Another method is the launch tower robotic arm gripping and recovery method, commonly known as "chopstick gripping". A large robotic arm on the launch tower grips the rocket from both sides when it is hovering. The rocket does not carry heavy landing legs, but the guidance, navigation and control system of the rocket's terminal stage has extremely high precision requirements. The landing accuracy needs to be controlled at the meter level or even the centimeter level. Any deviation may cause capture failure.

[0005] The two methods described above illustrate that existing rocket recovery methods always involve an extreme trade-off between landing accuracy and dry weight. Landing accuracy affects recovery costs and reliability, while rocket dry weight affects rocket payload capacity. The inventors aimed to find a reasonable balance between landing accuracy and dry weight, seeking a method that does not excessively affect rocket payload capacity while appropriately reducing recovery costs, thus achieving a balance in practicality, economy, and reliability. Summary of the Invention

[0006] This application provides an electromagnetic sleeve device and landing method for the terminal landing of a launch vehicle, which can solve the problems of excessively increasing the dry weight of the rocket and the overly stringent requirements for the accuracy of the rocket's hovering attitude, and achieve a reasonable balance between the two.

[0007] To achieve the above objectives, this application adopts the following technical solution: An electromagnetic sleeve device for terminal landing of a launch vehicle includes an electromagnetic sleeve, a magnetic field source array mounted on the inner wall of the electromagnetic sleeve, and a magnetic element array mounted on the outer wall of the rocket. The electromagnetic sleeve is a conductive hollow cylinder with one end open and the other end closed. The height of the electromagnetic sleeve is the distance required for the rocket's terminal deceleration, and the inner diameter is larger than the outer diameter of the rocket. The magnetic field source array includes multiple layers of magnetic field sources arranged at intervals along the axial direction of the electromagnetic sleeve. Each layer of magnetic field sources includes an even number of magnetic field sources fixed at intervals along the circumference of the electromagnetic sleeve. The magnetic poles of the magnetic field sources are radially magnetized, and the magnetic poles of adjacent magnetic field sources are opposite in direction. The magnetic element array includes multiple layers of magnetic elements arranged at intervals along the axial direction of the rocket. Each layer of magnetic elements includes magnetic elements fixed at intervals along the circumference of the rocket, corresponding to the number of magnetic field sources. The magnetic poles of the magnetic elements are radially magnetized, and the magnetic poles of adjacent magnetic elements are opposite in direction. When the rocket's attitude is adjusted to enter the electromagnetic sleeve, the outer magnetic pole of each magnetic element is the same as the center magnetic pole of the corresponding magnetic field source.

[0008] In one implementation, an induced flaring section is installed on the electromagnetic sleeve. The induced flaring section is a hollow conical body with the larger diameter facing upwards.

[0009] Furthermore, the same magnetic field source array as that inside the electromagnetic sleeve is installed inside the induced flaring section, with the number of magnetic field sources in each layer being equal to the number of magnetic field sources in each layer of the electromagnetic sleeve and their positions corresponding.

[0010] In one implementation, the magnetic field source and magnetic element are one of an arc-shaped permanent magnet, an electromagnetic coil winding, or a superconducting magnet.

[0011] In one implementation, the magnetic field source is mounted on the inner wall of the electromagnetic sleeve via a support base made of a non-ferromagnetic conductive material, and the magnetic element is mounted on the rocket via a mounting base made of a non-ferromagnetic conductive material. Both the support base and the mounting base are integral thin-walled sleeves with open ends. Alternatively, only the mounting base is fixed on the rocket without any magnetic element.

[0012] In one implementation, the electromagnetic sleeve is divided into multiple independent modular electromagnetic units. The induced flaring section is an independent electromagnetic unit. The electromagnetic sleeve is divided into multiple electromagnetic units along the axial direction. Each electromagnetic unit has an independent magnetic field source and heat dissipation structure. The magnetic field source is an electromagnetic coil winding. The electromagnetic unit is powered by an independent power supply and controller. During the rocket's descent, each electromagnetic unit adjusts the magnetic field strength in real time according to the rocket's descent position and speed, so that the braking force changes according to a preset curve.

[0013] In one implementation, a locking mechanism is provided at the bottom of the electromagnetic sleeve. After the rocket comes to a complete stop at the bottom of the electromagnetic sleeve, the locking mechanism fixes the rocket at the center of the electromagnetic sleeve.

[0014] In one implementation, the electromagnetic sleeve wall has a double-layer structure, with a heat dissipation structure between the outer and inner walls. The heat dissipation structure is either a water-cooled pipe or an air-cooled fin.

[0015] A landing method for achieving terminal landing of a launch vehicle using an electromagnetic sleeve device includes the following steps: S1 Preparation Phase: Install electromagnetic sleeve devices on the landing site and set up magnetic element arrays on the outside of the rocket; S2 Induction Entry Phase: The rocket reduces its speed to the predetermined contact speed in the air above the landing site through the preceding deceleration means, and enters the electromagnetic sleeve with an attitude close to vertical. S3 Lateral self-alignment stage: The magnetic field source inside the electromagnetic sleeve generates a lateral restoring force pointing towards the central axis of the sleeve between the magnetic field source and the rocket's magnetic components, pushing the rocket to the position of the central axis of the sleeve; S4 Eddy deceleration phase: Simultaneously with the S3 lateral self-centering phase, the rocket is subjected to a braking force in the opposite direction to its velocity, and its velocity at the bottom of the electromagnetic sleeve is reduced to zero or the predetermined safe landing velocity. S5 Locking and Parking Phase: After the rocket comes to a complete stop at the bottom of the electromagnetic sleeve, it is secured by the locking mechanism at the bottom of the electromagnetic sleeve.

[0016] The beneficial effects of the technical solutions provided in this application include at least the following: The inner diameter or induced flaring section opening of the electromagnetic sleeve in this invention can be much larger than the outer diameter of the rocket, allowing the rocket to enter the electromagnetic sleeve device with a lateral deviation of meters. Compared with the centimeter-level accuracy of existing tower robotic arm clamping schemes, this significantly relaxes the requirements for rocket terminal landing accuracy. Therefore, it greatly simplifies the design of the rocket's terminal guidance, navigation, and control systems, reducing the complexity and cost of the corresponding control systems. The lower guidance accuracy requirement also improves recovery reliability. On the other hand, the weight of the magnetic components on the rocket is controlled within 5% of the rocket's weight. Existing landing legs and their deployment mechanisms typically weigh 1.5 to 3 tons, accounting for 5% to 10% of the rocket's dry weight. The dry weight of the rocket in this device is significantly smaller. Therefore, this invention finds a reasonable balance between excessively increasing the rocket's dry weight and the stringent accuracy requirements for the rocket's hovering attitude, making the method and device of this invention both practical and economical.

[0017] The magnetic field source and magnetic elements of the device of the present invention simultaneously achieve lateral self-centering and eddy current deceleration, achieving two goals at once, eliminating the need for separate centering and deceleration mechanisms, and greatly simplifying the structure of the device.

[0018] The rocket deceleration and self-centering functions of this invention are achieved entirely through non-contact electromagnetic force, possessing real-time self-adjustment and compensation capabilities, and can recover the rocket to the center landing position with very high precision; the response of electromagnetic force is instantaneous, the rocket recovery process is short, and the recovery efficiency is high; direct physical contact between components is eliminated, there is no wear on the components, and the equipment has a long service life.

[0019] This invention does not rely on any of the power supply, sensors, controllers, or actuators, has very few failure modes, and significantly improves reliability.

[0020] The present invention features an induction flare section on the electromagnetic sleeve. The rocket enters the electromagnetic sleeve through the opening of the induction flare section, which increases the opening area for receiving the rocket by a factor of two, greatly relaxing the requirements for rocket landing accuracy and increasing recovery reliability. With the addition of the induction flare section, the diameter of the electromagnetic sleeve section can be reduced to accommodate the rocket, and the number of magnetic field source arrays can also be reduced accordingly, resulting in lower cost.

[0021] The electromagnetic sleeve of the present invention is made of ferromagnetic material. An integrated support base and mounting base are provided to install the magnetic field source array and the magnetic element array respectively, which avoids interference with the magnetic field distribution and simplifies the assembly process of the electromagnetic sleeve device.

[0022] The electromagnetic sleeve of this invention can be divided into multiple independent modular electromagnetic units. Each modular electromagnetic unit can adjust the magnetic field strength of its unit in real time according to the current position and speed of the rocket, so that the braking force changes according to a preset curve. Different preset braking force curves are adapted to rockets of different sizes and masses, and the preset braking force curve can be precisely controlled to meet the requirements of the rocket being served.

[0023] After the rocket of this invention comes to a complete stop at the bottom of the electromagnetic sleeve, the locking mechanism fixes the rocket at the center position of the electromagnetic sleeve to meet the stability requirements during subsequent operations.

[0024] A heat dissipation structure is provided on the electromagnetic sleeve to remove the heat generated by eddy currents during braking, keeping the temperature of the electromagnetic sleeve and the magnetic field source below the demagnetization temperature of the permanent magnet, ensuring the normal operation of the magnetic field and improving the reliability of the device. Attached Figure Description

[0025] Figure 1 Here is a cross-sectional view of an embodiment of the device of the present invention. Figure 2 Here is a cross-sectional view of an embodiment of the device of the present invention that includes an induced flaring section. Figure 3 This is a cross-sectional view of the magnetic field source array configured in the induced flaring section of the present invention. Figure 4 The arrangement of magnetic field sources and magnetic elements in each layer of the electromagnetic sleeve device of the present invention, and the magnetic field direction diagram; Figure 5 Here is a cross-sectional view of the support base and mounting base of the present invention; The symbols in the diagram represent the following meanings: 1-Electromagnetic sleeve, 2-Magnetic field source, 4-Magnetic element, 5-Inducing flaring section, 6-Support base, 7-Mounting base, 8-Locking mechanism. Detailed Implementation

[0026] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0027] Hereinafter, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of embodiments of this disclosure, unless otherwise stated, "a plurality of" means two or more.

[0028] The electromagnetic sleeve device and landing method for the terminal landing of a launch vehicle of the present invention utilize the interaction between the magnetic field source inside the electromagnetic sleeve device on the ground and the magnetic components on the rocket to generate two forces. The first is a reverse eddy current braking force along the rocket's descent direction, passively decelerating the rocket within the electromagnetic sleeve. The second is a lateral restoring force pointing towards the central axis of the sleeve, ensuring that even with a meter-level lateral deviation during initial entry, the rocket is automatically attracted by the magnetic field and aligned with the central axis of the electromagnetic sleeve. This invention achieves deceleration and alignment in a purely passive mode, independent of power sources, sensors, and mechanical mechanisms. It significantly relaxes the guidance accuracy requirements for the terminal phase of the launch vehicle without excessively increasing the dry weight of the launch vehicle, achieving a reasonable balance between relaxed landing accuracy and reduced dry weight. It is a rocket recovery method that is both practical and economical.

[0029] This invention discloses an electromagnetic sleeve device for terminal landing of a launch vehicle, such as... Figure 1 As shown, it includes an electromagnetic sleeve 1 fixed to the landing site, a magnetic field source array installed on the inner wall of the electromagnetic sleeve 1, and a magnetic element array installed on the outer wall of the rocket.

[0030] The electromagnetic sleeve 1 is a conductive hollow cylinder with one open end (top) and the other closed end (bottom). For example, it can be a high-strength steel structure cylinder. The opening of the electromagnetic sleeve 1 faces upward, and the closed end is fixed to the landing site, specifically to a concrete base. The rocket is recovered in a vertical position in the electromagnetic sleeve 1. The height (axial length) of the electromagnetic sleeve 1 is greater than the length of the rocket, which should be the distance required for the rocket's terminal deceleration. The inner diameter of the electromagnetic sleeve 1 is greater than the outer diameter of the rocket.

[0031] The direction of the height of the electromagnetic sleeve 1 and the rocket is called the axial direction, the direction of the cross-section perimeter is called the circumferential direction, and the direction from the center outward on the cross-section is called the radial direction.

[0032] The electromagnetic sleeve 1 is preferably made of a non-ferromagnetic material, such as aluminum alloy, because non-ferromagnetism can reduce interference with the magnetic field region of the magnetic field source.

[0033] like Figure 1 , 2 As shown, the magnetic field source array includes multiple magnetic field sources 2 arranged at intervals along the axial direction of the electromagnetic sleeve 1, preferably with magnetic field sources 2 arranged on the entire inner wall of the electromagnetic sleeve 1.

[0034] Figure 4 The diagram shows the arrangement of magnetic field sources and magnetic elements in each layer of the electromagnetic sleeve device, as well as the magnetic field direction. As can be seen, each layer of magnetic field sources includes an even number of magnetic field sources 2 spaced at fixed intervals along the circumference of the electromagnetic sleeve 1. The magnetic poles of magnetic field sources 2 are magnetized radially, i.e., they are divided into N and S poles radially. Adjacent magnetic field sources 2 have opposite pole directions, forming a closed-loop magnetic field (the arrows in the diagram indicate the magnetic field direction). Figure 4 As shown, the magnetic poles of the eight magnetic field sources 2 (arc magnets) facing the center of the cross-section are arranged at intervals of NSNSNSNS, forming eight closed-loop magnetic fields. The internal space of the electromagnetic sleeve 1 has a magnetic field region formed by multiple closed-loop magnetic fields.

[0035] The magnetic field source array is preferably arranged at equal intervals in the circumferential and axial directions.

[0036] The magnetic element array includes multiple layers of magnetic elements spaced apart along the rocket axis. The magnetic elements 4 can cover the entire rocket, or in order to reduce the dry weight of the rocket, the magnetic elements 4 can be set only in the lower middle part of the rocket.

[0037] like Figure 4 As shown, each layer of magnetic elements includes magnetic elements 4, which are fixedly spaced along the circumference of the rocket and correspond to the same number of positions as the magnetic field sources 2. The magnetic elements 4 are magnetized radially, that is, they are divided into N poles and S poles in the radial direction, and the magnetic poles of adjacent magnets are opposite in direction. Figure 4 In the middle, the magnetic poles of the eight magnetic elements 4 (arc magnets) facing outward are arranged at intervals of NSNSNSNS.

[0038] The magnetic element array is preferably arranged at equal intervals in both the circumferential and axial directions.

[0039] During its vertical descent within the electromagnetic sleeve 1, the rocket exhibits minimal rotation, and the circumferential relative position of the rocket and the electromagnetic sleeve 1 remains constant. Therefore, when adjusting the rocket's attitude to guide it into the electromagnetic sleeve 1, the outward-facing magnetic poles of each magnetic element 4 align with the center-facing magnetic poles of the corresponding magnetic field source 2. Figure 4 The outermost magnetic element of the #1 magnetic source is the N pole, and the corresponding #1 magnetic source 2 facing the center is also the N pole. The same applies to the other 7 groups. According to the principle of like poles repelling each other, the magnetic source 2 that is closer to the rocket off-center has a greater repulsive force with the magnetic element 4, while the magnetic source 2 on the opposite side is farther away from the magnetic element 4 and has a smaller repulsive force. The difference in repulsive force on the rocket is the lateral restoring force F. The magnitude of F is approximately proportional to the distance of the rocket from the center of the electromagnetic sleeve 1. That is, the further the rocket is from the center, the greater the lateral restoring force. The lateral restoring force pushes the rocket toward the center of the electromagnetic sleeve 1, thus achieving automatic centering of the rocket.

[0040] Based on parameters such as the rocket's volume, weight, and velocity, determine the minimum magnetic induction intensity near the inner wall of the electromagnetic sleeve 1 and the minimum magnetic induction intensity at its center. Then, further determine the circumferential number of magnetic field source arrays and magnetic element arrays, the axial layer spacing, and the magnetic field strength of individual magnets. For example, each layer of magnetic field sources is not limited to... Figure 4 The eight magnetic field sources 2 shown can also be any even number of poles such as 4, 6, 12, or 16. The more magnets there are, the greater the lateral gradient of the magnetic field at the center of the electromagnetic sleeve 1, the stronger the lateral restoring force, and the greater the axial braking force on the rocket. However, the more magnetic elements 4 there are, the greater the dry weight of the rocket. The total weight of the magnetic elements 4 should not exceed 5% of the dry weight of the rocket.

[0041] The rocket recovery process of this device is as follows: When the returning rocket is decelerated to a predetermined contact speed and its attitude is adjusted to near vertical position over the landing site using existing reverse thrust, attitude control, and grid fin deceleration methods, it enters the electromagnetic sleeve 1 through the top opening. When the rocket first enters the electromagnetic sleeve 1, its center is usually off-center from the centerline of the sleeve. During its descent, the rocket gradually enters the magnetic field region generated by the magnetic field source 2. The interaction between the magnetic field source 2 and the magnetic element 4 automatically generates a lateral restoring force pointing towards the central axis of the electromagnetic sleeve 1. This lateral restoring force gradually adjusts the rocket to the central axis position of the electromagnetic sleeve 1 during its downward motion, achieving self-centering. After the rocket enters the electromagnetic sleeve 1, the magnetic element 4 descends at high speed relative to the electromagnetic sleeve 1. The electromagnetic sleeve 1 cuts the magnetic field lines of the magnetic element 4, and the magnetic flux through the closed area of ​​the electromagnetic sleeve 1 changes, causing eddy currents to be generated inside the electromagnetic sleeve 1. The Ampere force of the magnetic field of the magnetic element 4 on the electromagnetic sleeve 1 reacts to the magnetic element 4. According to Lenz's law, the force acting on the magnetic element 4 (rocket) is opposite to the direction of the rocket's motion, that is, a braking force is generated in the opposite direction of the rocket's motion. The braking force causes the rocket to decelerate and brake axially inside the electromagnetic sleeve 1. When the rocket reaches the bottom of the electromagnetic sleeve 1, its speed is reduced to zero or the predetermined safe landing speed.

[0042] As one possible implementation method, such as Figure 2 As shown, an induced flaring section 5 is installed on the electromagnetic sleeve 1. The induced flaring section 5 is a hollow conical body with the larger diameter facing upwards. Figure 2 In this design, the opening diameter of the induced flare section 5 is four times the inner diameter of the electromagnetic sleeve 1. The rocket enters the electromagnetic sleeve 1 through the opening of the induced flare section 5, and the opening area for receiving the rocket increases exponentially, greatly relaxing the requirements for rocket landing accuracy and increasing recovery reliability. With the addition of the induced flare section 5, the diameter of the electromagnetic sleeve 1 can be reduced to just be enough to accommodate the rocket, and the number of magnetic field source arrays can also be reduced accordingly. This makes the electromagnetic sleeve device smaller in size and lower in cost.

[0043] The induced flare section 5 is designed to reduce the accuracy of rocket landing. The rocket's deceleration and centering process mainly occurs within the electromagnetic sleeve 1, so the height of the induced flare section 5 is much smaller than that of the electromagnetic sleeve 1. Figure 2 The height of the electromagnetic sleeve 1 is 1 / 4 of the height. The induced flaring section 5, which has a smaller height, does not need to be equipped with a magnetic field source array.

[0044] The opening diameter and height of the induced flare section 5 need to be specifically set according to the rocket's speed and the precision of the rocket's control system.

[0045] As another possible implementation of the induced flaring section 5, see Figure 3The rocket enters the electromagnetic sleeve device at a relatively high speed, and needs to decelerate immediately in the induction flare section 5. The same magnetic field source array as the electromagnetic sleeve 1 is installed in the induction flare section 5. The inner wall of the induction flare section 5 is conical with varying cross-sectional diameter. The number of magnetic field sources in each layer is still equal to the number of magnetic field sources in each layer of the electromagnetic sleeve 1, and their positions correspond.

[0046] To facilitate understanding of the technical solution of this invention, an example of an electromagnetic sleeve device is provided. The outer diameter of the recovered rocket is approximately 3.7 meters. The electromagnetic sleeve 1 has an inner diameter of 5 meters, an outer diameter of 6 meters, and a height of 40 meters. The top opening diameter of the induced flaring section 5 is 20 meters (4 times the inner diameter of the electromagnetic sleeve) and a height of 10 meters (1 / 4 of the height of the electromagnetic sleeve). The inner walls of the electromagnetic sleeve 1 and the induced flaring section 5 are equipped with magnetic field source arrays arranged with a layer spacing of 1.5 meters and 8 magnets evenly distributed in each layer. The outer wall of the rocket is also equipped with a magnetic element array arranged with a layer spacing of 1.5 meters and 8 magnets evenly distributed in each layer. In the cross-section, each magnetic field source 2 is opposite to a magnetic element 4 with the same magnetic pole. The circumferential coverage of the magnetic element 4 is approximately 50%. The axial coverage length is 10 meters, and the total mass of the magnetic element array is about 800 kg (the existing landing leg support and deployment mechanism weigh 1.5 to 3 tons). The rocket enters the induction flare section 5 with a vertical speed of 20 m / s to 50 m / s and an attitude close to vertical (verticality error less than 5 degrees). The lateral position deviation is on the order of meters (within 16 meters). The rocket is decelerated from an initial speed of about 20-50 m / s in the electromagnetic sleeve 1 to the predetermined safe landing speed of <2 m / s at the bottom of the sleeve.

[0047] As can be seen from the above, the inner diameter of the electromagnetic sleeve 1 or the opening of the induced flaring section 5 of the present invention can be much larger than the outer diameter of the rocket, allowing the rocket to enter the electromagnetic sleeve 1 with a lateral deviation of meters. Compared with the centimeter-level accuracy of the existing tower robotic arm clamping scheme, the landing accuracy requirements of the rocket in the terminal stage are significantly relaxed. Therefore, the design of the rocket's terminal guidance, navigation, and control system is greatly simplified, and the complexity and cost of the corresponding control system are reduced. The lower guidance accuracy requirement also improves the reliability of recovery. On the other hand, the weight of the magnetic component 4 on the rocket is controlled within 5% of the rocket's weight. The existing landing legs and their deployment mechanisms are usually 1.5 to 3 tons, accounting for 5% to 10% of the rocket's dry weight. Therefore, the dry weight of the rocket is significantly reduced by this device. Thus, the present invention finds a reasonable balance between the problem of excessively increasing the dry weight of the rocket and the stringent accuracy requirements for the rocket's hovering attitude, making the method and device of the present invention both practical and economical.

[0048] The rocket deceleration and self-centering functions of this invention are achieved entirely through a non-contact method using magnetic fields, possessing real-time self-adjustment and compensation capabilities, and can recover the rocket to the center landing position with very high precision; the response of electromagnetic force is instantaneous, making the rocket recovery process short and efficient; and the non-contact method eliminates direct physical contact between components, resulting in no wear on components and a long service life of the equipment.

[0049] The magnetic field source and magnetic elements of the device of this invention simultaneously achieve lateral self-centering and eddy current deceleration, achieving two goals at once. There is no need to set up a separate centering mechanism and deceleration mechanism, which greatly simplifies the structure of the recovery device.

[0050] This invention does not rely on any of the power supply, sensors, controllers, or actuators, has very few failure modes, and significantly improves reliability.

[0051] The electromagnetic sleeve 1 can be cylindrical, elliptical, polygonal prism, or other shapes. Its inner wall can be arranged with a magnetic field source array as described above, as long as its internal space can accommodate the vertical entry of the rocket. As a preferred embodiment, such as... Figure 2 The electromagnetic sleeve 1 is a cylindrical body, and the induced flared section 5 is a cone. The cylindrical cross-section facilitates the uniform arrangement of the magnetic field source 2 and the magnetic element 4, and the magnetic field distribution on the cross-section is uniform, which simplifies the design and manufacturing difficulty.

[0052] As a possible implementation, the magnetic field source 2 and the magnetic element 4 can be arc-shaped permanent magnets ( Figure 4 One of the following: electromagnetic coil winding or superconducting magnet.

[0053] The arc-shaped permanent magnet is magnetized radially. The permanent magnet structure is simple and reliable.

[0054] The electromagnetic coil winding needs to be powered by an external power source. Its advantage is that the magnetic field strength can be actively adjusted by controlling the power supply current to adapt to the recovery requirements of rockets with different masses and entry speeds. When the device is not in use, the power supply can be turned off to save energy. In case of failure, the braking force can be rapidly enhanced by switching the current direction in an emergency.

[0055] Superconducting magnets have higher magnetic field strength and lower energy consumption.

[0056] As one possible implementation method, such as Figure 5As shown, the magnetic field source 2 is mounted on the inner wall of the electromagnetic sleeve 1 via a support 6 made of non-ferromagnetic conductive material, and the magnetic element 4 is mounted on the rocket via a mounting base 7 made of non-ferromagnetic conductive material. The support 6 and mounting base 7 can be made of copper or aluminum, and both are integral thin-walled sleeves with open ends. After the magnetic field source array and the magnetic element array are arranged and installed on the support 6 and mounting base 7 respectively, they are then fixed as a whole inside the electromagnetic sleeve 1 and mounted on the rocket, significantly simplifying the assembly process and increasing assembly efficiency. Furthermore, the support 6 and the electromagnetic sleeve 1, both acting as closed conductors, generate eddy currents under the influence of the moving magnetic field generated by the magnetic element 4. The support 6 is also subjected to the Ampere force of the magnetic element, generating a braking force in the opposite direction of the rocket's motion according to Lenz's law. Simultaneously, the mounting base 7, moving with the rocket, also generates eddy currents in the magnetic field generated by the magnetic field source, and a repulsive Ampere force is generated between the mounting base 7 (rocket) and the magnetic field source 2. These two additional braking forces enhance the deceleration effect of the device on the rocket.

[0057] As an alternative to the above implementation, only the mounting base 7 is fixedly installed on the rocket, without the magnetic element 4. During the rocket's descent, the mounting base 7 moves in the magnetic field generated by the magnetic field source 2, generating eddy currents inside. The mounting base 7 experiences an Ampere force opposite to its velocity direction within the magnetic field of the magnetic field source 2, achieving braking. When the rocket (mounting base 7) deviates from the center of the electromagnetic sleeve 1, the distances of each section of the mounting base 7 from the magnetic field source 2 are different. The magnetic field is stronger closer to the magnetic field source 2, resulting in larger eddy currents and a larger radial Ampere force. The magnetic field is weaker on the side of the conductive ring farther from the magnetic field source 2, with smaller eddy currents and a smaller magnetic force. The resultant forces on both sides are unbalanced, and the net resultant force is a lateral restoring force pointing towards the center of the electromagnetic sleeve 1. The rocket gradually approaches the center, achieving automatic centering. This embodiment does not install magnetic elements, reducing the dry weight of the rocket and thus increasing its carrying capacity.

[0058] As one possible implementation, the electromagnetic sleeve 1 can be divided into multiple independent modular electromagnetic units. Figure 2The overall electromagnetic sleeve 1 is divided into five units, with the induced flaring section 5 serving as an independent modular electromagnetic unit. The electromagnetic sleeve 1 is further divided into multiple modular electromagnetic units along the axial direction, each with a height of several meters. Each modular electromagnetic unit contains an independent magnetic field source 2 and a heat dissipation structure. The magnetic field source 2 consists of electromagnetic coil windings. Each modular electromagnetic unit is powered by an independent power supply and controller. During rocket descent, each modular electromagnetic unit can adjust its magnetic field strength in real time according to the rocket's current position and speed, causing the braking force to change according to a preset curve. For example, the preset curve might be: a smaller braking force in the initial stage to avoid impact overload, a larger braking force in the middle stage to facilitate rapid deceleration, and a smaller braking force in the final stage to avoid rebound. This closed-loop control method makes the braking process smoother. Different preset braking force curves are suitable for rockets of different sizes and masses, and the requirements of the rocket being served can be met through precise control of the preset braking force curves.

[0059] The internal electromagnetic sleeve device, which contains a large array of magnetic field sources and is used repeatedly, requires maintenance after each recovery mission. The modular electromagnetic unit can be repaired and replaced individually, which greatly improves maintenance efficiency and reduces economic costs.

[0060] As one possible implementation, a locking mechanism 8 is provided at the bottom of the inner interior of the electromagnetic sleeve 1, see... Figure 1 , Figure 2 After the rocket comes to a complete stop at the bottom of the electromagnetic sleeve 1, the locking mechanism 8 fixes the rocket at the center of the electromagnetic sleeve 1 to meet the stability requirements during subsequent operations. The locking mechanism 8 can be one of the following locking methods: mechanical gripper, magnetic suction, clamping, inflatable positioning bladder, ratchet locking, shape memory alloy locking, etc. Any mechanism that can fix the rocket can be used as the locking mechanism 8 of the electromagnetic sleeve device of this invention.

[0061] In one embodiment, the electromagnetic sleeve 1 has a double-layer structure, with a heat dissipation structure between the outer and inner walls. The heat dissipation structure is used to remove the heat generated by eddy currents during the braking process of the electromagnetic sleeve 1. The heat dissipation structure is a water-cooled pipe or an air-cooled fin, so that the temperature of the electromagnetic sleeve device is kept below the demagnetization temperature of the permanent magnet, ensuring the normal operation of the magnetic field and improving the reliability of the device.

[0062] The present invention also provides a landing method for achieving terminal landing of a launch vehicle using the above-mentioned electromagnetic sleeve device, comprising the following steps: S1 Preparation Phase: Install electromagnetic sleeve devices on the landing site of the ground or sea platform, and set up an array of magnetic elements on the outside of the rocket.

[0063] S2 Induction Entry Phase: The rocket reduces its speed to the predetermined contact speed over the landing site through preceding reverse thrust, attitude control, and grid fin deceleration methods. The predetermined contact speed is generally 10 to 100 meters per second. The rocket's attitude is close to vertical, and it enters the electromagnetic sleeve 1 through the upper opening.

[0064] S3 Lateral self-alignment stage: When the rocket deviates from the central axis of the electromagnetic sleeve 1 during its descent, a lateral restoring force is generated between the magnetic field source 2 inside the electromagnetic sleeve 1 and the magnetic element 4 of the rocket, pointing towards the central axis of the sleeve. This lateral restoring force gradually pushes the rocket back to the central axis of the sleeve during its descent, thus achieving self-alignment between the rocket and the electromagnetic sleeve 1.

[0065] S4 Eddy Current Deceleration Stage: Simultaneously with the S3 lateral self-centering stage, as the rocket descends at high speed relative to the magnetic field region inside the electromagnetic sleeve 1, eddy currents (induced currents) are generated inside the electromagnetic sleeve 1. The magnetic element 4 (rocket) is subjected to an Ampere force in the opposite direction to the rocket's velocity, which is the axial braking force of the rocket. The braking force causes the rocket to be passively decelerated along the axial direction, and the rocket's velocity at the bottom of the electromagnetic sleeve 1 is reduced to zero or the predetermined safe landing speed.

[0066] S5 Locking and Parking Phase: After the rocket comes to a complete stop at the bottom of the electromagnetic sleeve 1, it is fixed by the locking mechanism 8 at the bottom of the electromagnetic sleeve 1, forming a rigid connection between the rocket and the electromagnetic sleeve 1 to meet the stability requirements during subsequent operations.

[0067] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0068] The above embodiments merely illustrate several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. An electromagnetic sleeve device for terminal landing of a launch vehicle, characterized in that, It includes an electromagnetic sleeve (1), a magnetic field source array installed on the inner wall of the electromagnetic sleeve (1), and a magnetic element array installed on the outer wall of the rocket; The electromagnetic sleeve (1) is a conductive hollow cylinder with one end open and the other end closed. The height of the electromagnetic sleeve (1) is the distance required for the rocket to decelerate at the end stage, and the inner diameter is larger than the outer diameter of the rocket. The magnetic field source array includes multiple layers of magnetic field sources arranged at intervals along the axial direction of the electromagnetic sleeve (1). Each layer of magnetic field sources includes an even number of magnetic field sources (2) fixed at circumferential intervals along the electromagnetic sleeve (1). The magnetic poles of the magnetic field sources (2) are radially magnetized, and the magnetic poles of adjacent magnetic field sources (2) are opposite in direction. The magnetic element array includes multiple layers of magnetic elements arranged at intervals along the rocket axis. Each layer of magnetic elements includes magnetic elements (4) that are fixed at intervals along the rocket circumferentially and are equal in number to the magnetic field source (2). The magnetic poles of the magnetic elements (4) are radially magnetized, and the magnetic poles of adjacent magnetic elements (4) are opposite in direction. When the rocket attitude is adjusted to enter the electromagnetic sleeve (1), the magnetic poles of each magnetic element (4) facing outward are the same as the magnetic poles of the corresponding magnetic field source (2) facing the center.

2. The apparatus according to claim 1, characterized in that, An induced flaring section (5) is installed on the electromagnetic sleeve (1), and the induced flaring section (5) is a conical hollow body with the large diameter facing upward.

3. The apparatus according to claim 2, characterized in that, The same magnetic field source array as that in the electromagnetic sleeve (1) is installed in the induced flaring section (5), with the number of magnetic field sources in each layer being equal to the number of magnetic field sources in each layer of the electromagnetic sleeve (1) and their positions corresponding.

4. The apparatus according to claim 2, characterized in that, The magnetic field source (2) and the magnetic element (4) are one of the following: an arc-shaped permanent magnet, an electromagnetic coil winding, or a superconducting magnet.

5. The apparatus according to claim 1 or 2, characterized in that, The magnetic field source (2) is installed on the inner wall of the electromagnetic sleeve (1) through a support base (6) made of non-ferromagnetic conductive material. The magnetic element (4) is installed on the rocket through a mounting base (7) made of non-ferromagnetic conductive material. The support base (6) and the mounting base (7) are both thin-walled sleeves that are not closed at both ends.

6. The apparatus according to claim 5, characterized in that, Only the mounting base (7) is fixed on the rocket, and the magnetic element (4) is not installed.

7. The apparatus according to claim 2, characterized in that, The electromagnetic sleeve (1) is divided into multiple independent modular electromagnetic units. The induced flaring section (5) is an independent electromagnetic unit. The electromagnetic sleeve (1) is divided into multiple electromagnetic units along the axial direction. The electromagnetic unit is equipped with an independent magnetic field source (2) and heat dissipation structure. The magnetic field source (2) is an electromagnetic coil winding. The electromagnetic unit is powered by an independent power supply and controller. During the rocket descent, each electromagnetic unit adjusts the magnetic field strength in real time according to the rocket's descent position and speed, so that the braking force changes according to the preset curve.

8. The apparatus according to claim 1 or 2, characterized in that, A locking mechanism (8) is provided at the bottom of the electromagnetic sleeve (1). After the rocket stops completely at the bottom of the electromagnetic sleeve (1), the locking mechanism (8) fixes the rocket at the center of the electromagnetic sleeve (1).

9. The apparatus according to claim 1 or 2, characterized in that, The electromagnetic sleeve (1) has a double-layer structure, with a heat dissipation structure between the outer and inner walls. The heat dissipation structure is a water-cooled pipe or an air-cooled fin.

10. A landing method for achieving terminal landing of a launch vehicle using the electromagnetic sleeve device according to any one of claims 1-9, characterized in that, Includes the following steps: S1 Preparation Phase: Install electromagnetic sleeve devices on the landing site and set up magnetic element arrays on the outside of the rocket; S2 Induction entry phase: The rocket reduces its speed to the predetermined contact speed in the air above the landing site through the preceding deceleration means, and enters the electromagnetic sleeve (1) with an attitude close to vertical. S3 Lateral self-alignment stage: The magnetic field source (2) inside the electromagnetic sleeve (1) and the rocket magnetic element (4) generate a lateral restoring force pointing towards the central axis of the sleeve, pushing the rocket to the position of the central axis of the sleeve; S4 Vortex deceleration stage: Simultaneously with the S3 lateral self-centering stage, the rocket is subjected to a braking force in the opposite direction to its velocity, and its velocity at the bottom of the electromagnetic sleeve (1) is reduced to zero or the predetermined safe landing speed. S5 Locking and parking phase: After the rocket comes to a complete stop at the bottom of the electromagnetic sleeve (1), it is secured by the locking mechanism (8) at the bottom of the electromagnetic sleeve (1).

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