A point-to-point receiver self-balancing rocket recovery system and method

Abstract

The application discloses a point-to-interface receiver self-balancing rocket recovery system and method. The system comprises a mobile self-balancing base capable of active driving and a rocket receiver installed thereon. The receiver base of the rocket receiver is provided with a plurality of precise docking grooves, each of which is used for matching engagement with a corresponding docking convex force body at the bottom of a return rocket stage. As a variant, the rocket receiver further comprises a funnel-shaped guide structure, the inner wall of which is provided with a plurality of guide grooves respectively upwardly extended from the precise docking grooves. When the return rocket stage descends, one docking convex force body enters one of the guide grooves, and the remaining docking convex force bodies subsequently enter the respective precise docking grooves. The movable holding arm is used in combination with the funnel-shaped guide structure or independently for a point-to-interface receiver without the funnel. After receiving, a sensor subsystem detects the inclination angle and angular velocity of the carrier, and a controller drives the mobile platform to generate a correction motion, so as to stabilize the return rocket stage.

Description

Technical Field

[0001] This invention belongs to the field of reusable launch vehicle recovery, specifically relating to a system and method for receiving, carrying, and stabilizing a vertical return rocket stage using an actively movable self-balancing base and a point-to-point docking rocket receiver with precise docking grooves. Background Technology

[0002] Reusable rocket stages typically return via propulsion and vertical landing, or are captured using external infrastructure. In vertical landing with landing legs, the deployable legs, locking mechanism, and energy-absorbing components must all be carried by the rocket stage, increasing dry mass and system complexity, and placing higher demands on landing speed, attitude, and ground conditions.

[0003] Fixed towers, grid structures, or hook-type capture devices can transfer some equipment to external facilities, but typically require high terminal positioning accuracy, dedicated airborne capture structures, or large fixed facilities, and their deployment location and operating environment are limited. For fixed receivers, the rocket must reach the predetermined location precisely, with limited lateral capture tolerance.

[0004] On the other hand, when the receiver engages with the return rocket stage at discrete support positions, if a matching interface is not designed for the main load-bearing structure at the rocket's base, local contact pressure may concentrate in thin-walled areas. If the receiver only passively bears the load, the high-center-of-gravity rocket stage may also tend to overturn under residual lateral velocity, wind load, or engagement impact. Therefore, a recovery system is needed that can utilize the existing load-bearing path at the rocket's base, achieve precise positioning, and actively stabilize the high-center-of-gravity load-bearing body after engagement. Summary of the Invention

[0005] The present invention aims to provide a point-to-point receiver self-balancing rocket recovery system and method, which sets the main receiving, bearing, impact dissipation and stabilization functions on a reusable mobile base, and uses the precise docking groove on the receiver base to establish a positionally defined load-bearing connection with the docking convex force-bearing body at the bottom of the returning rocket stage.

[0006] The mobile self-balancing base includes a mobile platform, a drive system, a sensor subsystem, and a controller. The mobile platform is capable of active movement on the ground, a deck, a work platform surface, or other external foundation surface located below it and supporting its movement. The rocket receiver is mounted on the mobile self-balancing base and is used to receive and carry the return rocket stage.

[0007] In the basic point docking configuration, the receiver base is equipped with multiple precision docking grooves around the predetermined descent axis of the return rocket stage. Correspondingly, multiple docking convex force-bearing bodies are positioned at the bottom of the return rocket stage. The movable self-balancing base adjusts its planar position and yaw angle, allowing each docking convex force-bearing body to directly enter its corresponding precision docking groove along the descent direction. This establishes a force-bearing connection at discrete force-bearing positions while simultaneously limiting the circumferential and radial displacements of the return rocket stage.

[0008] In the variant with a funnel-shaped guide structure, the upwardly widening funnel-shaped guide structure provides a larger initial capture opening. Its inner wall is provided with several circumferentially distributed fan-shaped guide grooves. Each fan-shaped guide groove extends upwards from its corresponding bottom precision docking groove along the inner wall of the funnel, gradually widening from bottom to top. Adjacent fan-shaped guide grooves intersect, connect, or partially overlap at the groove boundaries on the upper edge of the funnel, forming a circumferentially continuous or substantially continuous guide entry area, thereby reducing the possibility of convex impact bodies falling into the non-guided area between adjacent grooves. During the descent of the return rocket stage, one docking convex impact body first enters one of the fan-shaped guide grooves and establishes circumferential guidance. The remaining docking convex impact bodies slide down the inner surface of the funnel as the return rocket stage adjusts its orientation, gradually aligning with their respective fan-shaped guide grooves and bottom precision docking grooves. The unfolding angle, upper opening size, and inner wall profile of the funnel-shaped guide structure are determined based on the outer envelope, axial and radial positions of the lower engine and engine nozzle of the return rocket stage, as well as the permissible descent position and attitude deviations, to maintain a preset safety clearance and avoid collisions throughout the entry and descent process. As an alternative structural option, the fan-shaped guide groove can be replaced with a guide groove of equal width.

[0009] Upon reception, the support plate, rocket receiver, and return rocket stage together form the upper support structure carried by the mobile platform. The inertial measurement unit obtains its tilt angle and angular velocity in real time. Based on the dynamic stability principle of an inverted pendulum, the controller calculates corrective control quantities according to the attitude deviation and drives the mobile platform to generate corrective displacement and / or corrective acceleration along the tilt direction. This causes the resultant support reaction force on the external foundation surface to generate a restoring torque relative to the center of mass of the support structure, and maintains or returns the center of mass projection to the effective support area of ​​the mobile platform. This closed-loop control continues until the attitude parameters enter a preset stable range.

[0010] Damping elements can be placed between the support joint plate and the moving platform to absorb and dissipate the joint impact; mechanical limits or equivalent constraints are set between the support joint plate and the moving platform to limit relative displacement and form a defined ultimate load path. The system's active self-balancing is achieved by the controlled movement of the moving platform relative to the external foundation surface.

[0011] The present invention also provides a corresponding recovery method and a modular rocket receiver for mounting on a mobile self-balancing base. A funnel-shaped guide module can be optionally mounted above a point-to-point receiver base and shares motion, sensing, and control components with the receiver base.

[0012] Compared with the prior art, the present invention has the following beneficial effects: 1. By placing the main capture, load-bearing, shock dissipation, and stabilization equipment on a reusable ground or deck mobile base, the number of deployable recovery mechanisms carried by the return rocket stage can be reduced.

[0013] 2. The mobile self-balancing base can adjust its position within the recovery area and generate a restoring torque through closed-loop translation after engagement, thereby improving the effective capture tolerance and reducing the risk of overturning of high-center-of-gravity load-bearing structures.

[0014] 3. The precise matching and engagement of the docking groove and the docking convex force-bearing body can form a clear load path at multiple predetermined load-bearing positions, and simultaneously achieve circumferential and radial positioning of the return rocket stage.

[0015] 4. Multiple fan-shaped guide slots extending upwards from the precise docking groove at the bottom and gradually widening allow any docking convex object to first enter its adjacent guide slot and establish circumferential guidance, eliminating the need for multiple docking convex objects to enter the slot simultaneously in the initial stage. Adjacent slot openings intersect, connect, or partially overlap at the upper edge of the funnel, forming a continuous or nearly continuous guide entry area, further increasing the probability of first-time entry. The remaining docking convex objects are then guided along the inner surface of the funnel to the corresponding precise docking groove at the bottom. The funnel's expansion angle and inner wall profile are determined by the outer contour and position of the engine and nozzle, balancing capture tolerance and collision avoidance safety clearance; the equal-width guide slots provide a simpler structural alternative.

[0016] 5. For the return stage after propellant has been consumed, the load-bearing capacity of the launch support hardpoints under launch quality conditions can provide structural margin for recovery conditions, provided that the joint impact, dynamic load, fatigue and reuse verification have been completed.

[0017] 6. The precise docking groove can transfer loads and manage impacts through load-bearing blocks, heat-resistant layers, and buffer layers, and can be adapted to different return rocket stages through replaceable or calibrable bearings.

[0018] 7. Damping elements are used to reduce the peak impact of the joint, and mechanical limits are used to maintain a defined load path; neither replaces the active self-balancing control of the moving platform.

[0019] 8. The installation and operation of the movable holding arm are not based on the funnel-type guide structure. It can be combined with the funnel configuration to provide auxiliary lateral holding, or it can be used in the direct point docking configuration without the funnel, thereby expanding the applicability of the same holding solution. Attached Figure Description Figure 1 This is a schematic diagram of the structure of a rocket recovery device equipped with a point-to-point receiver during the approach phase of the returning rocket stage; Figure 2 yes Figure 1 The diagram shows the structure of the device during the lower stage of the return rocket. Figure 3 yes Figure 2 Sectional view along the middle AA; Figure 4 This is a schematic diagram of a point-to-point rocket recovery device equipped with a funnel-shaped guide groove and a fan-shaped guide groove during the approach phase of the return rocket stage. Figure 5 yes Figure 4 A sectional view along the center CC; Figure 6 yes Figure 4 A sectional view along the middle edge BB; Figure 7 yes Figure 4 A top view of the funnel-shaped guide structure in the middle; Figure 8 yes Figure 4 The diagram shows the structure of the device during the lower stage of the return rocket. Figure 9 yes Figure 4 A schematic diagram of the device during the precise docking and stabilization phase. Figure 10 yes Figure 9 Sectional view along AA; Figure 11 yes Figure 4 The diagram shows the process by which the device moves in response to the unbalanced state of the carrier and achieves stability after capture, as shown in the diagram. Figure 12 This is a schematic diagram of a point-to-point rocket recovery device equipped with a funnel-shaped guide structure with equal-width guide grooves during the approach phase of the return rocket stage. Figure 13 yes Figure 12 The diagram shows the structure of the device during the lower stage of the return rocket. Figure 14 yes Figure 12 A schematic diagram of the device during the precise docking and stabilization phase. Figure 15 yes Figure 14 A cross-sectional view along BB; Figure 16 yes Figure 14 Sectional view along AA; Figure 17 yes Figure 12The diagram illustrates the process by which the device moves in response to the unbalanced state of the carrier and achieves stability after capture, as shown.

[0020] In the diagram, 100 is the movable self-balancing base; 110 is the support joint plate; 111 is the engine clearance hole; 120 is the moving platform; 130 is the damping element; 140 is the point docking bearing; 141 is the precision docking groove; 200 is the point docking receiver with a funnel-shaped guide structure; 210 is the funnel-shaped guide structure; 212 is the guide groove; 213 is the precision docking groove; 220 is the movable holding arm; 230 is the holding piece; 300 is the point docking receiver; 400 is the return rocket stage; and 401 is the docking convex force-bearing body. Detailed Implementation The following are specific embodiments of the present invention, which are described in conjunction with the accompanying drawings. However, the present invention is not limited to these embodiments.

[0021] I. System Overall Structure like Figures 1 to 17 As shown, the mobile self-balancing base 100 can travel on prepared landing sites, launch pads, fire-resistant surfaces, ship decks, barges, offshore platforms, or other external foundation surfaces. The mobile platform 120 can adopt a wheeled, tracked, wheel-tracked hybrid, or track-guided structure, and its drive system includes at least one of differential wheel speed drive, coordinated wheel direction drive, independent steering wheel module, steering wheel drive module, omnidirectional wheel, Mecanum wheel, track module, and track-guided module.

[0022] The rocket receiver is installed on the mobile self-balancing base 100 and is configured as a basic point-to-point receiver 300 or a point-to-point receiver 200 with an added funnel-shaped guide structure, depending on the mission conditions.

[0023] The support plate 110 is used to transfer the load of the rocket receiver to the moving platform 120. A damping element 130 and a mechanical limiting structure may be provided between the support plate 110 and the moving platform 120. The damping element 130 may include at least one of the following: a spring, a hydraulic damper, a pneumatic damper, an elastomeric damper, a magnetorheological damper, an eddy current damper, a friction damper, a crushable element, or an active control actuator. The mechanical limiting structure is used to limit the relative displacement of the support plate 110 and to form a defined ultimate load path when a preset displacement or load condition is reached.

[0024] During the engagement phase, the damping element 130 reduces the peak impact load; during the active stabilization phase, the controller changes the line of action of the support reaction force by driving the moving platform 120 to move relative to the external base surface.

[0025] The rocket receiver is configured as a basic point-to-point receiver 300, or as a point-to-point receiver 200 with an added funnel-shaped guide structure 210 on the point-to-point structure, depending on the mission conditions.

[0026] The overall structure of this system integrates a mobile self-balancing base 100 with multiple maneuvering drive modes, a modularly configurable rocket receiver, and a support joint plate 110 with damping and force limiting mechanisms. This enables the transfer of rocket recovery equipment from the rocket carrier to the ground, reducing the dead weight of the rocket payload. It can not only efficiently absorb and dissipate the strong impact load at the moment of engagement and establish a safe ultimate load path, but also actively adjust the support reaction force through the controlled translation of the mobile self-balancing base 100, dynamically eliminating the overturning tendency of the high center of gravity rocket stage. This significantly improves the recovery stability and structural safety of the rocket body under complex landing loads and environmental disturbances.

[0027] II. Point-to-point receiver with funnel-guided structure The point-to-point receiver 200 with a funnel-shaped guide structure includes a funnel-shaped guide structure 210 disposed above the receiver base with its opening facing away from the moving platform 120. The upper opening of the funnel-shaped guide structure 210 is used to receive the return rocket stage 400, which has lateral deviation, and its diameter gradually decreases along the direction of receiving the return rocket stage 400. The funnel-shaped guide structure 210 can be conical, truncated conical, bell-shaped, polygonal, segmented, semi-open, or formed by discrete guide rails.

[0028] The inner wall of the funnel-shaped guide structure 210 is provided with multiple guide grooves 212. During the descent and engagement of the return rocket stage 400, any one of the multiple docking convex force-bearing bodies 401 located at the bottom of the return rocket stage 400 slides into the corresponding guide groove 212 and moves in the direction of receiving the return rocket stage 400 (i.e., sliding downwards), thereby constraining and locking the circumferential yaw angle of the return rocket stage 400. At the same time, the remaining docking convex force-bearing bodies 401 are controlled by the overall constraint and will move down synchronously and in the same direction along the inner wall of the funnel-shaped guide structure 210 until each docking convex force-bearing body 401 enters the corresponding precision docking groove 213 at the bottom, completing the circumferential and radial positioning.

[0029] The unfolding angle, upper opening size, lower opening size, and inner wall profile of the funnel-shaped guide structure 210 are determined based on the outer contour envelope of the lower engine and engine nozzle of the return rocket stage 400, the axial and radial positions of the engine and engine nozzle relative to the rocket body axis, the expected descent position deviation, and attitude deviation. Within the permissible entry path and relative attitude range, the engine, engine nozzle, and other lower protruding components maintain a preset safety clearance with the inner wall of the funnel-shaped guide structure 210, thereby preventing these components from colliding with the funnel wall or guide groove 212. The preset safety clearance can further account for measurement errors, control errors, structural deformation, wind load disturbances, and relative motion margins during the engagement process.

[0030] The bottom or adjacent outer wall of the return rocket stage 400 is provided with multiple docking convex force-bearing bodies 401 that mate with guide grooves 212 and precision docking grooves 213. After the return rocket stage 400 enters the funnel-shaped guide structure 210, one of the multiple docking convex force-bearing bodies 401 first enters a guide groove 212 adjacent to its circumferential position within a continuous or substantially continuous guide entry area at the upper edge of the funnel, and slides downward along the guide groove 212. Since each docking convex force-bearing body 401 forms an integral part with the return rocket stage 400, the engagement of the first docking convex force-bearing body 401 with the guide groove 212 constrains the circumferential orientation of the return rocket stage 400, thereby guiding the remaining docking convex force-bearing bodies 401 to slide downward and inward along the inner surface of the funnel-shaped guide structure 210. As the return rocket stage 400 continues its descent, the remaining docking convex support bodies 401 gradually enter their respective guide slots 212 or align with their bottom precision docking grooves 213, until multiple docking convex support bodies 401 fall into their respective bottom precision docking grooves 213, thereby completing circumferential and radial precise positioning and establishing multiple load-bearing connections. This process does not require multiple docking convex support bodies 401 to simultaneously enter their respective guide slots 212 in the initial stage.

[0031] It should be further explained that, typically, before liftoff, the rocket is supported on a launch pad, with the support points on the launch pad aligned with the docking convex load-bearing body 401 on the rocket body. The rated load-bearing capacity of this docking convex load-bearing body 401 is usually designed based on the rocket's liftoff weight, and since the liftoff weight is much greater than the empty weight of the recovered first stage, this rated load-bearing capacity is generally set to more than ten times the weight of the recovered first stage. Therefore, the corresponding load-bearing parts on the rocket body do not require substantial reinforcement, as their own stress design already provides a significant load-bearing margin.

[0032] Depending on the specific design and manufacturing requirements, the guide groove 212 can be implemented in the following two ways: 1. Sector-shaped guide groove configuration: The guide groove 212 is a fan-shaped guide groove. Multiple fan-shaped guide grooves are circumferentially distributed along the inner wall of the funnel-shaped guide structure 210. Their positions correspond one-to-one with the positions of the multiple precision docking grooves 213. The diameter of the fan-shaped guide groove gradually decreases along the direction of receiving the return rocket stage 400 until it is the same as the diameter of the precision docking groove 213 at the bottom, so that its upper entrance has a larger circumferential capture range than the bottom precision docking groove 213. Two adjacent fan-shaped guide grooves intersect or connect at the edge (i.e., upper edge) of the funnel-shaped guide structure 210 on the side away from the moving platform 120, thereby forming a circumferentially continuous or substantially continuous guide entry area at this edge of the funnel-shaped guide structure, and reducing non-guided ridges or gaps between adjacent grooves that may hinder the docking convex force-bearing body 401 from entering the groove. The fan-shaped guide groove 212 may be defined by two lateral guide surfaces that approach each other in the descending direction and a load-bearing guide surface located between them. The guide surfaces transition continuously or in stages with the precision docking grooves 213.

[0033] 2. Equal-width guide groove configuration: The guide groove 212 is a guide groove of equal width. Multiple guide grooves of equal width are circumferentially distributed along the inner wall of the funnel-shaped guide structure 210. Their positions also correspond one-to-one with the multiple precision docking grooves 213. The diameter of the guide groove of equal width is constant along the direction of receiving the return rocket stage 400, and the transverse cross-sectional shape and size of the guide groove of equal width are the same as or basically the same as the transverse cross-sectional shape and size of the precision docking groove 213. When the return rocket stage 400 descends, a docking convex force-bearing body 401 first enters one of the guide grooves of equal width and establishes circumferential guidance. Then, the remaining docking convex force-bearing bodies 401 slide down the inner surface of the funnel to the corresponding precision docking groove 213 at the bottom. This structure can provide a non-fan-shaped guide scheme that is easy to process and control in size while retaining the single-point first-entry groove guide principle.

[0034] The support joint plate 110 is provided with an engine clearance hole 111, allowing the engine, nozzle, or other lower protruding components to pass through without serving as the main load-bearing fulcrum. Multiple precision docking grooves 213 are arranged around the engine clearance hole 111, so that the docking load is transferred from the docking convex force-bearing body 401 to the moving self-balancing base 100 via the receiver base.

[0035] To assist in limiting lateral tilting, the rocket receiver also includes multiple movable holding arms 220 arranged circumferentially around a predetermined descent axis. A movable holding arm 220 is circumferentially arranged around the predetermined descent axis of the return rocket stage 400. One end of the arm is hinged to the receiver base or support plate 110, and the other end is provided with a holding plate 230. The movable holding arm 220 remains open during the approach phase of the return rocket stage 400 and rotates inward after the return rocket stage 400 enters the predetermined holding position, so that the holding plate 230 contacts the rocket body to provide auxiliary lateral holding and / or limit tipping. The movable holding arm 220 has two configurations for different receiver types: 1. The movable holding arm 220 can be combined with the funnel-shaped guide structure 210; 2. The movable holding arm 220 is independently set on the point-to-point receiver 300 which is not equipped with the funnel-type guide structure 210.

[0036] In the latter configuration, the movable holding arm 220 closes according to a preset action sequence before, during or after the multiple docking convex force-bearing bodies 401 directly enter the corresponding precision docking grooves 213. The main axial force-bearing connection of the return rocket stage 400 is still formed by the multiple docking convex force-bearing bodies 401 and the corresponding precision docking grooves 213.

[0037] The docking receiver 200 with funnel-shaped guide structure provided in this application, through the combination of a large-opening funnel and an asymmetric guidance mechanism of "single-point entry into the slot for circumferential locking and sliding down to the other points", significantly improves the system's fault tolerance rate in capturing rocket landing yaw and horizontal deviation, eliminates the stringent control requirements of simultaneous alignment of multiple points, and provides two optional solutions in terms of structure: a fan-shaped guide slot with no receiving blind zone and an equal-width guide groove with high processing convenience. With the active restraint of the articulated movable holding arm 220, it provides ultra-large tolerance lateral anti-tipping protection for high center of gravity rockets throughout their entire life cycle, from dynamic sliding in to final landing and locking.

[0038] III. Point-to-point receiver The point-to-point receiver 300 includes a receiver base and multiple point-to-point bearings 140 arranged circumferentially around a predetermined descent axis of the return rocket stage 400. Each point-to-point bearing 140 forms a precision docking groove 141, the position and shape of which match the corresponding docking convex force-bearing body 401 on the bottom of the return rocket stage 400. The point-to-point bearings 140 can be fixed, replaceable, or calibrable to allow for replacement of interface components or calibration of installation positions for different rocket stages.

[0039] In embodiments without the funnel-shaped guide structure 210, the point-to-point receiver 300 can be independently configured with the aforementioned movable holding arm 220. The movable self-balancing base 100 first adjusts its planar position and yaw angle to align the multiple docking convex force-bearing bodies 401 with the precision docking groove 141; when the returning rocket stage 400 reaches the predetermined holding position, the movable holding arm 220 closes inward and provides auxiliary lateral holding without changing the load-bearing path where the precision docking groove 141 bears the main axial load.

[0040] As the return rocket stage 400 approaches, the movable self-balancing base 100 adjusts its planar position and yaw angle according to the position, attitude, and yaw direction of the return rocket stage 400, ensuring that multiple precision docking grooves 141 are positioned on the descent path of their respective docking convex support bodies 401. As the return rocket stage 400 continues its descent, each docking convex support body 401 directly enters and settles into its corresponding precision docking groove 141, thereby establishing a load-bearing connection and limiting the circumferential and radial displacement of the return rocket stage 400.

[0041] The precision docking groove 141 can be a spherical groove, conical groove, V-shaped groove, U-shaped groove, prismatic groove, keyway groove, or an irregularly shaped groove surrounded by multiple bearing surfaces. Its bottom bearing surface mainly transmits the axial load of the return rocket stage 400, while the lateral positioning surface transmits the lateral load and provides circumferential and radial positioning. The bearing surface can be equipped with replaceable load-bearing blocks, heat-resistant layers, friction-reducing layers, buffer layers, or combinations thereof.

[0042] The docking convex load-bearing body 401 is connected to or integrally formed with the main load-bearing structure of the return rocket stage 400, and may include a launch support boss, a launch locking boss, a load-bearing boss connected to the thrust frame, a load-bearing boss connected to the lower skirt reinforcement structure, a load-bearing boss connected to the ring frame, a load-bearing boss connected to the engine section support structure, or other convex load transfer structures.

[0043] In one embodiment, the docking convex force-bearing body 401 utilizes an existing load-bearing interface that is engaged by a launch support mechanism or a locking mechanism before launch of the return rocket stage 400. During launch, the launch support mechanism disengages from the interface when the engine reaches the predetermined thrust and takeoff begins; during recovery, the corresponding docking convex force-bearing body 401 enters a precise docking groove 141 on the receiver base, thereby reusing the existing main load-bearing path during the recovery phase.

[0044] The mass of a rocket stage before launch is typically greater than its return mass after propellant depletion. Therefore, the aforementioned launch supports or locking interfaces may have structural load-bearing margins suitable for recovery. Whether to utilize this margin should be determined based on a review of the specific rocket stage for recovery engagement impact, lateral loads, local contact stress, fatigue, thermal environment, and repeated service life.

[0045] Positioning sensors, visual positioning devices, proximity sensors, force measuring elements, or pressure sensors can be installed in the precision docking groove 141 or the point docking bearing 140. The controller determines whether the multiple docking convex force-bearing bodies 401 are accurately positioned based on the positioning status and contact load of each interface, and can trigger a mechanical locking component after confirming the positioning to prevent the docking convex force-bearing bodies 401 from retracting in the disengagement direction.

[0046] The point-to-point receiver 300 achieves high-precision, interference-free direct point-to-point constraint by employing a replaceable or calibrable precision docking groove 141, combined with the active attitude adjustment of the movable self-balancing base 100 and the lateral holding of the movable holding arm 220. Furthermore, by reusing the existing support and locking main load-bearing interfaces before the launch vehicle stage, it fully utilizes the structural strength margin of the rocket, avoiding the safety hazards and quality penalties caused by adding additional recovery load-bearing structures to the rocket body. At the same time, combined with sensing sensors and anti-detachment mechanical locking mechanisms, it ensures the accuracy of rocket landing judgment and the stability of immediate locking after recovery.

[0047] IV. Self-balancing working principle After the return rocket stage 400 is received, the support joint plate 110, the rocket receiver, and the return rocket stage 400 constitute a high-center-of-gravity upper support structure carried by the mobile platform 120. The sensor subsystem is configured to detect the unbalanced state of the rocket receiver and the support structure formed with the received return rocket stage 400. The inertial measurement unit in the sensor subsystem utilizes the outputs of gyroscopes and accelerometers, and obtains the tilt angle, angular velocity, and optionally linear acceleration through filtering or signal fusion. The controller is communicatively connected to both the sensor subsystem and the drive system of the mobile platform 120, and is configured to control the mobile platform 120 to generate corrective motion based on the unbalanced state to stabilize the support structure.

[0048] Specifically, the controller compares the detected attitude state with the target stable attitude and uses the same inverted pendulum closed-loop control principle as the dynamic stability control in commercial self-balancing vehicles to determine the tilt direction of the carrier and the correction control quantity. The moving platform 120 generates controlled displacement and / or acceleration along the tilt direction, causing the line of action of the resultant support reaction force of the external foundation surface on the moving platform 120 to move towards the vertical projection direction of the center of mass of the carrier, thereby generating a restoring torque opposite to the overturning tendency.

[0049] During a continuous control cycle, the controller continuously updates the direction of movement, speed, and / or acceleration until the tilt angle and angular velocity enter a preset stable range, and maintains or returns the center of mass projection within the effective support area of ​​the moving platform 120. The control algorithm may employ proportional-derivative control, proportional-integral-derivative control, state feedback, linear quadratic control, model predictive control, sliding mode control, adaptive control, or a combination thereof.

[0050] In a PID example, let the tilt angles of the two orthogonal directions in the horizontal plane be respectively... , angular velocities are respectively , The linear accelerations are respectively , The platform speed command can then be written as: ; .

[0051] in: The proportional gain determines the system's response sensitivity to tilt. The differential gain provides damping and suppresses oscillations; To achieve integral gain and eliminate steady-state error; For feedforward gain, compensation is performed in advance based on acceleration prediction.

[0052] Each gain can be tuned based on the return rocket stage mass, center of gravity height, moving platform capability, and permissible impact level, and speed, acceleration, and travel limits can be set.

[0053] When the point-to-point receiver 300 is equipped with a contact load sensor, the controller can also compare the overall tilt direction obtained by the inertial measurement unit with the direction of the resultant torque formed by the loads measured at each precision docking groove 141. If the two are consistent, the overall stability control of the mobile platform 120 is executed; if the difference between the two exceeds a threshold, a prompt is issued indicating that the interface is not fully positioned or the load is abnormal, and the movement of the mobile platform 120 is restricted according to a preset safety strategy.

[0054] Overall, this self-balancing working principle is based on inverted pendulum control technology. It utilizes a multi-source sensing closed loop composed of inertial measurement and load sensors to drive the mobile self-balancing base 100 to actively generate corrective motion along the tilt direction of the rocket stage, transforming dynamic instability into controlled self-balancing. This not only accurately generates a reverse recovery torque to dynamically offset the strong overturning torque under external environmental disturbances, but also uses a verification and judgment mechanism of attitude data and interface force load to promptly diagnose abnormal states such as incomplete landing, greatly enhancing the stability of rocket anti-overturning control.

[0055] V. Recycling Methods like Figure 10 As shown, a method for recovering and returning a rocket stage using a point-to-point receiver and a mobile self-balancing base includes the following steps: S1. Track the position, velocity, attitude, and estimated engagement time of the returning rocket stage 400; S2. Move the self-balancing base 100 of the bearing point docking receiver 300 to the predicted interception position, and fine-tune the planar position and yaw direction according to the terminal state of the return rocket stage 400. S3. Execute either a direct point docking path or a funnel-guided point docking path according to the receiver configuration. When using the direct point docking path, adjust the planar position and yaw angle of the moving self-balancing base 100 so that multiple docking convex force-bearing bodies 401 directly enter the corresponding precision docking grooves 141, and close the movable holding arm 220 when the return rocket stage 400 reaches the predetermined holding position. When using the funnel-guided point docking path, one of the multiple docking convex force-bearing bodies 401 first enters one of the fan-shaped guide grooves 212 or equal-width guide grooves in the continuous or basically continuous guide entry area formed by the intersection, connection or partial overlap of the groove boundaries of adjacent fan-shaped guide grooves 212 at the upper edge of the funnel, and slides down along it to establish circumferential guidance, so that the remaining docking convex force-bearing bodies 401 slide down and inward along the inner surface of the funnel-type guide structure 210 until each docking convex force-bearing body 401 enters the corresponding precision docking groove 213 at the bottom. S4. The tilt angle and angular velocity of the carrier formed by the docking receiver 300 and the return rocket stage 400 are detected by the sensor subsystem. S5. Based on the unbalanced state of the carrier, the controller drives the mobile platform 120 in a closed loop to generate corrective displacement and / or corrective acceleration along the tilt direction until the carrier enters the preset stable range. Finally, after confirming that each docking convex force-bearing body 401 is accurately positioned, it is reliably locked back to the rocket stage 400 by mechanical locking components, articulated wing components or other retaining structures for subsequent transportation or disposal.

[0056] This recovery method achieves a high degree of adaptability in vertical rocket recovery operations under different landing deviations by establishing a time-series process including "state tracking, active alignment, multi-path adaptive docking, closed-loop self-balancing control, and physical locking." Utilizing the guidance control logic of "single-point capture to establish constraints - circumferential guidance - multi-point synchronous landing," it greatly reduces the control difficulty of instantaneous multi-point precise alignment. Furthermore, the inverted pendulum closed-loop self-balancing maneuver with immediate post-landing response ensures that the high-center-of-gravity rocket stage can quickly converge attitude disturbances and lock securely after completing the docking phase, significantly improving the fault tolerance and overall safety of the rocket's vertical recovery operation.

[0057] VI. Alternative Implementation Methods The funnel-shaped guide structure 210 can be used as an optional module installed above the point-to-point receiver 300. Without this module, multiple docking convex force-bearing bodies 401 directly enter the corresponding precision docking grooves 141 on the receiver base, and can be assisted by a separately configured movable holding arm 220 for lateral holding. When this module is installed, adjacent fan-shaped guide grooves 212 intersect, connect, or partially overlap at the upper edge of the funnel, forming a continuous or substantially continuous guide entry area. One docking convex force-bearing body 401 first enters one of the fan-shaped guide grooves 212 or equal-width guide grooves from this area and establishes circumferential guidance. The remaining docking convex force-bearing bodies 401 slide down the inner surface of the funnel-shaped guide structure 210 until multiple docking convex force-bearing bodies 401 respectively enter the corresponding precision docking grooves 213 at the bottom. The unfolding angle and inner wall profile of the funnel-shaped guide structure 210 should meet the collision safety clearance requirements of the engine and engine nozzle.

[0058] The mobile self-balancing base 100 can be sized to meet the requirements of land-based, shipboard, deck, or mixed operations, and can be equipped with thermal protection, flame deflectors, fire-resistant linings, sacrificial inserts, purge gases, splash protection, fire extinguishing systems, quick-release mechanisms, or as a backup support that can be deployed after the active stabilization phase.

[0059] The term "point connection" as used herein refers to a load-bearing connection with a finite contact area established between a convex load-bearing body and a matching groove at multiple discrete, predetermined, and identifiable load-bearing locations, and is not a zero-area point contact in the mathematical sense; the term "multiple" as used herein refers to at least two. Directional terms are used only to illustrate the relative relationships shown in the accompanying drawings and do not limit the system to a specific orientation.

[0060] The above embodiments are illustrative of the present invention and not intended to limit the scope of protection. Without departing from the concept of the present invention, those skilled in the art can make equivalent substitutions or combinations regarding the structural form, driving method, sensing method, and control algorithm.

Claims

1. A point-to-point receiver self-balancing rocket recovery system, characterized in that, include: A mobile self-balancing base includes a mobile platform capable of actively moving on an external base surface located below and supporting its movement, a drive system for driving the mobile platform, a sensor subsystem, and a controller. A rocket receiver, mounted on the mobile self-balancing base and used to receive and carry the return rocket stage, includes a receiver base and multiple precision docking grooves disposed on the receiver base. The multiple precision docking grooves are arranged circumferentially around a predetermined descent axis of the return rocket stage and are respectively configured to match and engage with multiple docking convex force-bearing bodies disposed at the bottom of the return rocket stage, so that each docking convex force-bearing body enters the corresponding precision docking groove to form a load-bearing connection and perform circumferential and radial positioning of the return rocket stage. The sensor subsystem is configured to detect the unbalanced state of the rocket receiver and the carrier formed with the received return rocket stage; The controller is communicatively connected to the sensor subsystem and the drive system, respectively, and is configured to control the mobile platform to generate corrective motion according to the unbalanced state in order to stabilize the carrier.

2. The system according to claim 1, characterized in that, The rocket receiver, the support plate for supporting the rocket receiver, and the received return rocket stage together constitute the upper support structure of the mobile platform. The sensor subsystem includes an inertial measurement unit with a gyroscope and an accelerometer, and is configured to obtain the tilt angle and angular velocity of the upper support body in real time based on the output signals of the gyroscope and the accelerometer. The controller is configured to determine the tilt direction and correction control quantity according to the deviation of the tilt angle and angular velocity relative to the target stable attitude, and output closed-loop control commands to the drive system, so that the mobile platform generates a correction displacement and / or correction acceleration along the tilt direction, so that the resultant support reaction force of the external base surface on the mobile platform generates a restoring moment opposite to the overturning tendency relative to the center of mass of the upper load-bearing body, and keeps or returns the center of mass projection of the upper load-bearing body to a preset stable position within the effective support area of ​​the mobile platform; The controller is also configured to continuously update the closed-loop control commands based on the attitude signals fed back by the sensor subsystem until the tilt angle and angular velocity enter a preset stable range.

3. The system according to claim 1 or 2, characterized in that, The drive system includes at least one of the following: differential wheel speed drive, coordinated wheel direction drive, independent steering wheel module, steering wheel drive module, omnidirectional wheel, Mecanum wheel, track module, and track guidance module.

4. The system according to claim 2, characterized in that, The rocket receiver is supported by the support joint plate, which includes one or more damping elements mounted on the mobile platform for absorbing and dissipating the impact load during the reentry rocket stage engagement.

5. The system according to claim 1, characterized in that, The rocket receiver also includes a funnel-shaped guide structure disposed above the receiver base. The opening of the funnel-shaped guide structure faces away from the moving platform, and the diameter of the funnel-shaped guide structure gradually decreases along the direction of receiving the return rocket stage. The inner wall of the funnel-shaped guide structure is provided with multiple guide grooves. During the descent and engagement of the return rocket stage, any one of the multiple docking convex force-bearing bodies slides into the corresponding guide groove and moves along the direction of receiving the return rocket stage. The remaining docking convex force-bearing bodies move down synchronously and in the same direction along the inner wall of the funnel-shaped guide structure until each docking convex force-bearing body enters the corresponding precision docking groove at the bottom.

6. The system according to claim 5, characterized in that, The guide groove is a fan-shaped guide groove, and multiple fan-shaped guide grooves are circumferentially distributed along the inner wall of the funnel-shaped guide structure. The positions of the multiple fan-shaped guide grooves correspond one-to-one with the positions of the multiple precision docking grooves. The diameter of the fan-shaped guide groove gradually decreases along the direction of receiving the return rocket stage until it is the same as the diameter of the precision docking groove. Adjacent fan-shaped guide grooves intersect or connect at the edge of the funnel-shaped guide structure on the side away from the moving platform, so that a circumferentially continuous or substantially continuous guide entry area is formed at the edge of the funnel-shaped guide structure on that side.

7. The system according to claim 5, characterized in that, The guide groove is a guide groove of equal width. Multiple guide grooves of equal width are circumferentially distributed along the inner wall of the funnel-shaped guide structure. The positions of the multiple guide grooves of equal width correspond one-to-one with the positions of the multiple precision docking grooves. The diameter of the guide groove of equal width is constant along the direction of receiving the return rocket stage. The transverse cross-sectional shape and size of the guide groove of equal width are the same as or substantially the same as the transverse cross-sectional shape and size of the precision docking groove.

8. The system according to claim 6 or 7, characterized in that, The unfolding angle, upper opening size, and inner wall profile of the funnel-shaped guide structure are determined based on the outer contour envelope of the lower engine and engine nozzle of the return rocket stage, the position of the engine and engine nozzle relative to the rocket body axis, and the expected descent position deviation and attitude deviation. This ensures that during the process of the return rocket stage entering the funnel-shaped guide structure and descending along it, the engine and engine nozzle maintain a preset safety gap with the inner wall of the funnel-shaped guide structure.

9. The system according to claim 2, characterized in that, The support joint plate is provided with an engine clearance hole that penetrates the receiver base and the support joint plate, and the engine clearance hole is located in the area enclosed by the plurality of precision docking grooves, wherein the engine clearance hole is configured to allow the engine, engine nozzle or other lower protruding components of the return rocket stage to pass through.

10. The system according to claim 1, characterized in that, The rocket receiver also includes a plurality of movable holding arms arranged circumferentially around the predetermined descent axis, with one end of each movable holding arm hinged to the receiver base and the other end provided with a holding piece; The movable holding arm is configured to remain in the open position during the approach phase of the return rocket stage and to rotate inward after the return rocket stage enters the predetermined holding position, so that the holding plate contacts the rocket body of the return rocket stage to provide lateral holding and / or limit overturning.

11. The system according to claim 6 or 7, characterized in that, The rocket receiver also includes a plurality of movable holding arms arranged circumferentially around the predetermined descent axis. One end of each movable holding arm is hinged to the top of the funnel-shaped guide structure, and the other end is provided with a holding piece. The movable holding arm is configured to remain in the open position during the approach phase of the return rocket stage and to rotate inward after the return rocket stage enters the predetermined holding position, so that the holding plate contacts the rocket body of the return rocket stage to provide lateral holding and / or limit overturning.

12. The system according to claim 1, characterized in that, The precision docking groove has a bottom bearing surface for bearing axial loads and a lateral positioning surface for bearing lateral loads and limiting circumferential and radial displacements. The precise docking groove is a spherical groove, a conical groove, a V-shaped groove, a U-shaped groove, a prism-shaped groove, a keyway-shaped groove, or an irregularly shaped groove surrounded by multiple bearing surfaces. The docking convex force-bearing body has an external shape that matches the corresponding precise docking groove. The bottom bearing surface and / or the lateral positioning surface are provided with replaceable load-bearing blocks, heat-resistant layers, friction-reducing layers, buffer layers, or combinations thereof.

13. The system according to claim 1, characterized in that, At least one of the precision docking grooves is provided with at least one of a positioning sensor, a proximity sensor, a force measuring element, and a pressure sensor; the controller is configured to determine whether each of the docking convex force-bearing bodies has entered the corresponding precision docking groove based on the detected placement state and / or contact load.

14. The system according to claim 1, characterized in that, At least one of the precision docking grooves is provided with a mechanical locking element, which is configured to restrict the corresponding docking convex force-bearing body from exiting in the disengagement direction after it enters the precision docking groove.

15. The system according to claim 1, characterized in that, The precise docking groove is set on a fixed, replaceable, or calibrable point docking support; the replaceable or calibrable point docking support is used to replace the corresponding support or adjust the installation position of the support according to the position and shape of the docking convex force-bearing body of different return rocket stages.

16. A method for recovering and returning a rocket stage using a point-to-point receiver and a moving self-balancing base, characterized in that, Including the following steps: S1. Track the position and preset engagement time of the return rocket stage; S2. Move the mobile self-balancing base carrying the point-to-point receiver to a preset interception position; S3. The multiple docking convex force-bearing bodies located at the bottom of the return rocket stage are respectively inserted into the corresponding precise docking grooves on the receiver base of the point docking receiver to establish a load-bearing connection and perform circumferential and radial positioning of the return rocket stage. S4. Detect the unbalanced state of the support structure formed by the point docking receiver and the return rocket stage; S5. Based on the unbalanced state, the moving platform of the self-balancing base is controlled in a closed loop to generate a corrective displacement and / or corrective acceleration until the carrier enters a preset stable range.

17. The method according to claim 16, characterized in that, When the point-to-point receiver is equipped with a funnel-shaped guide structure, one of the plurality of docking convex force-bearing bodies first enters one of the fan-shaped guide grooves in the continuous or substantially continuous guide entry area where the boundaries of adjacent guide grooves intersect or connect at the upper edge of the funnel-shaped guide structure, and slides down along the fan-shaped guide groove to provide circumferential guidance for the return rocket stage; causing the remaining docking convex force-bearing bodies to slide down along the inner surface of the funnel-shaped guide structure and gradually align with their respective corresponding fan-shaped guide grooves and precision docking grooves, until each docking convex force-bearing body enters the corresponding precision docking groove at the bottom.

18. The method according to claim 16, characterized in that, When the point docking receiver is not equipped with a funnel-shaped guide structure, the moving self-balancing base is controlled to adjust its planar position and yaw angle according to the position, attitude and yaw direction of the return rocket stage, so that the multiple precision docking grooves are respectively located on the descent path of the corresponding docking convex force-bearing body, and each docking convex force-bearing body directly enters the corresponding precision docking groove.

19. The method according to claim 16, characterized in that, The unbalanced state includes the tilt angle and angular velocity of the load-bearing body; the closed-loop control includes determining the tilt direction and correction control amount based on the tilt angle and angular velocity, and controlling the moving platform to move in the tilt direction, so that the combined support reaction force of the external foundation surface generates a restoring torque opposite to the overturning tendency relative to the center of mass of the load-bearing body, until the load-bearing body enters the preset stable range.

20. A rocket receiver for a point-to-point self-balancing rocket recovery system, characterized in that, include: The receiver base has a mounting interface for connection to a mobile self-balancing base; Multiple precision docking grooves are arranged circumferentially around the predetermined descent axis of the return rocket stage on the receiver base, and are respectively used to receive the corresponding docking convex force-bearing bodies set at the bottom of the return rocket stage. After the multiple docking convex force-bearing bodies enter the corresponding precision docking grooves, they form a load-bearing connection and limit the circumferential and radial displacement of the return rocket stage.

21. The rocket receiver according to claim 20, characterized in that, It also includes a funnel-shaped guide module that can be optionally installed above the receiver base. The funnel-shaped guide module has an upwardly enlarging opening and several circumferentially distributed fan-shaped guide grooves. Each of the fan-shaped guide grooves extends upward from a corresponding precision docking groove at the bottom along the inner wall of the funnel toward the opening and gradually widens. The adjacent fan-shaped guide grooves intersect or connect at the groove boundary on the upper edge of the funnel-shaped guide module to form a circumferentially continuous or substantially continuous guide entry area. This allows one of the multiple docking convex force-bearing bodies to first enter one of the fan-shaped guide grooves through the guide entry area and establish circumferential guidance. Subsequently, the remaining docking convex force-bearing bodies slide down the inner surface of the funnel and enter the corresponding precision docking grooves at the bottom.

22. The rocket receiver according to claim 20, characterized in that, The receiver base is connected to a support plate, the support plate having an engine clearance hole, and the receiver base having a plurality of point-fitting bearings arranged around the engine clearance hole. Each point-fitting bearing forms a precision mating groove and is fixed, replaceable, or calibrable.

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