Apparatus for micro-low gravity field landing simulation test based on vertical near-zero stiffness mechanism and use method thereof

Abstract

This invention provides a micro-low gravity field landing simulation test device based on a vertical near-zero stiffness mechanism, including a truss, a linear module, electromagnets, a probe simulator, a zero-stiffness mechanism, a companion vehicle, and a simulated star catalog. The truss is mounted on the simulated star catalog, with a guide rail laid in the middle of the catalog. The linear module is mounted on the truss directly above the guide rail, and an electromagnet is mounted on the moving block of the linear module. The linear module can be connected to the probe simulator via the electromagnets. The probe simulator is mounted to the companion vehicle via the zero-stiffness mechanism, and the companion vehicle can move on the guide rail. This invention is applicable to landing buffer ground tests for lunar, Martian, and other asteroid probes, providing a high-fidelity, full-physics simulation simulator test for landing leg landings, especially active leg soft landings.

Description

Technical Field

[0001] This invention belongs to the aerospace field, and in particular relates to a device and method for simulating landing in a micro-low gravity field based on a vertical near-zero stiffness mechanism. Background Technology

[0002] The soft landing of a microgravity field probe is a crucial step in extraterrestrial exploration. During landing, the impact loads the probe endures directly affect its landing safety and the implementation of subsequent exploration work. The landing process is irreversible and faces numerous uncertainties, making it a challenging and high-risk mission. Every year, several spacecraft models experience quality problems due to landing impacts, including control component failures, structural damage, and failure to meet performance specifications due to excessive impact. Due to a lack of understanding of the coupling collision mechanism under landing impact loads, research on the interaction characteristics between stellar regolith and the probe is currently in the experimental, improvement, and re-experimentation stage. Therefore, improving the accuracy of ground simulation experiments for microgravity field landings is of significant research importance.

[0003] Currently, commonly used methods for simulating landing in microgravity fields include the scaled-down model direct descent method, accelerated descent method, neutral buoyancy method, passive counterweight method, pendulum method, and inclined plane method. Among these, the accelerated descent method, neutral buoyancy method, and pendulum method have high testing costs; the accelerated descent method has high accuracy but extremely short testing time; the neutral buoyancy method and pendulum method have low testing accuracy. The scaled-down model direct descent method changes the mass to match the gravitational pull of a celestial body, therefore the system energy is lower than the actual state, which is a flaw in assessing landing performance. The passive counterweight method is limited by interference factors such as friction, resulting in low accuracy. The inclined plane method has moderate testing costs, but the testing process and data processing are complex, and the testing risk is high.

[0004] Patent CN113104241A describes a method and apparatus for simulating the initial flight state of a probe landing test. The apparatus includes a clamping rod, a tower, a universal lifting device, and a hoisting rope. The method involves setting the test starting point and simulating the corresponding flight parameters of the probe, and provides rules for setting key control parameters during the test. This allows for setting a reasonable starting point and accurately simulating the corresponding flight state parameters and operating modes of the probe in landing verification tests, ensuring a smooth transition of the probe into subsequent landing flight and achieving the goal of comprehensive verification of the landing process. This method is suitable for ground verification tests of hard landings of probes. However, for probes undergoing soft landings with landing cushioning, a cushioning process occurs after landing, and this landing process is highly dynamic. Due to the presence of the hoisting rope, this patent cannot achieve a rapid response in such a high-dynamic environment. Therefore, a ground verification system suitable for soft landings with active legs is needed. Summary of the Invention

[0005] In view of this, the present invention aims to propose a device and method for simulating landing in a microgravity field based on a vertical near-zero stiffness mechanism. By using a vertical zero stiffness + servo servo mechanism, high dynamic response and high-precision tracking of the vertical support force can be achieved, greatly improving simulation accuracy. By adjusting the magnitude of the vertical support force through vertical support, the additional gravity of Earth can be unloaded, simulating the microgravity environment of extraterrestrial bodies such as the Moon, Mars, and asteroids. The linear module can drive the probe simulator to achieve horizontal acceleration, and the release of the electromagnet can obtain the vertical landing velocity. The entire system can be combined to complete the overall landing buffer ground verification test.

[0006] To achieve the above objectives, the technical solution of the present invention is implemented as follows:

[0007] The micro-low gravity field landing simulation test device based on a vertical near-zero stiffness mechanism includes a truss, linear module, electromagnet, probe simulator, zero stiffness mechanism, accompanying vehicle and simulated star table; it can realize ground verification test of probe landing buffer landing, especially covering the hard landing of passive legs and the soft landing of active legs.

[0008] The truss is mounted on a simulated star catalog, with a guide rail laid in the middle of the catalog. A linear module is mounted on the truss directly above the guide rail. The moving block of the linear module is equipped with an electromagnet, and the linear module can be connected to the detection simulator via the electromagnet.

[0009] The detection simulator is mounted to the accompanying vehicle via a zero-stiffness mechanism, and the accompanying vehicle is capable of moving on the runway.

[0010] Furthermore, the truss is constructed from a ball-and-stick mechanism and connected to a linear module. The simulator is connected to the truss structure to realize horizontal acceleration and vertical descent landing buffer conditions. Its structure has good stability and can withstand tons of weight.

[0011] Furthermore, the linear module is connected to the truss structure to provide horizontal speed for the detection simulator. When there is no horizontal speed, the linear module does not need to move and releases the electromagnet in place to obtain vertical speed. When there is both horizontal and vertical speed, the linear module drives the detector simulator to move and releases the electromagnet after reaching the predetermined horizontal speed.

[0012] Furthermore, the electromagnet serves as a connection between the linear module and the detector simulator. The switching on and off of the electromagnet enables the simulator to be released and fall. When there is horizontal and vertical speed, the electromagnet is automatically switched on and off by detecting the horizontal speed of the module.

[0013] Furthermore, the detection simulator includes a simulator frame, an air-bearing ball bearing, a planar air cushion, an air-bearing platform, and landing legs. The detection simulator needs to simulate the mass and inertia of a real probe, as well as the release of six degrees of freedom. The air-bearing ball bearing releases three rotational degrees of freedom, the planar air cushion slides on the small platform, releasing two translational degrees of freedom, and the vertical degree of freedom is realized by a zero-stiffness mechanism, simulating a real landing load for the landing legs, making the simulation effect more realistic and effective.

[0014] Furthermore, the zero-stiffness mechanism includes a magnetostrictive zero-stiffness actuator and a servo servo actuator. The magnetostrictive zero-stiffness actuator is composed of structures such as electromagnets. This structure can maintain a constant force value within a range of ±5mm. Therefore, during the landing process of the probe simulator, facing highly dynamic landing characteristics, the magnetostrictive zero-stiffness actuator is a purely passive method, which can follow the landing motion characteristics of high impact and short stroke as needed. The servo servo actuator is composed of a lead screw, motor, etc. During the landing process of the probe simulator, landing buffering is required, and the buffering stroke is relatively large. The stroke of the magnetostrictive zero-stiffness actuator alone is far from sufficient to meet the landing motion requirements. Because of its dynamic characteristics, a servo servo is connected in series below the magnetostrictive zero stiffness. The position change of the zero stiffness is detected by a grating, and the movement of the servo mechanism is controlled. When the magnetostrictive zero stiffness changes displacement, the servo servo will respond quickly to compensate for the motion stroke during the landing buffer process. The zero stiffness mechanism unloads the weight of the probe simulator. When simulating lunar landing, the zero stiffness mechanism needs to bear 5 / 6 of the simulator's weight to simulate 1 / 6g of gravitational acceleration. The simulation landing method for other extraterrestrial bodies is the same, only the unloading weight of the zero stiffness mechanism needs to be changed.

[0015] Furthermore, the accompanying vehicle moves together with the landing simulation device. When the detector only has vertical velocity, the accompanying vehicle does not need to follow; it only needs to remain stationary and release the electromagnet to achieve a landing buffer at vertical velocity. When there is both horizontal and vertical velocity, the linear module drives the simulator to accelerate horizontally, and the accompanying vehicle follows until the simulator lands and stabilizes, at which point the accompanying vehicle can stop. Due to the presence of the air-bearing platform, the following accuracy of the accompanying vehicle in the control system can be reduced.

[0016] Furthermore, the simulated star surface is designed to simulate the surface characteristics of extraterrestrial objects, and the star surface characteristics such as pits, bumps, and slopes can be realized through design.

[0017] Furthermore, the detection simulator simulates the mass and inertia of a real detector, as well as the release of its six degrees of freedom.

[0018] Furthermore, the zero-stiffness mechanism can maintain a constant force value within a range of ±5mm.

[0019] The method of using the micro-low gravity field landing simulation test device based on a vertical near-zero stiffness mechanism includes the following steps:

[0020] S1. Assembly of the test device system;

[0021] S2. Pre-test adjustment: Adjust the zero-stiffness mechanism to balance 5 / 6 of the mass of the detection simulator, with the remaining 1 / 6 of the mass balanced by the suspension force at the top of the detection simulator; energize the electromagnet, and connect the linear module to the detection simulator through the electromagnet.

[0022] S3, Begin the experiment;

[0023] When there is only vertical velocity, the electromagnet is de-energized, and the probe simulator is subjected to an unbalanced 1 / 6g gravity force and undergoes 1 / 6g free fall motion until the probe simulator falls onto the simulated star table, completing the landing simulation experiment;

[0024] When there is both horizontal and vertical speed, the linear module drives the probe simulator to move, and the accompanying vehicle follows the movement; when the preset horizontal speed is reached, the electromagnet is de-energized and the probe simulator is released. The probe simulator is affected by 1 / 6g of gravity and accelerates downward by 1 / 6g. By combining with the horizontal speed, the probe simulator moves in a parabolic motion, and the accompanying vehicle always follows the movement until the simulator lands on the simulated star table and the state is stable.

[0025] S4. When simulating microgravity of other extraterrestrial bodies, the landing simulation test under different gravitational accelerations is achieved by adjusting the support force of the zero-stiffness mechanism. The process is the same as the above process.

[0026] Compared with existing technologies, the micro-low gravity field landing simulation test device based on a vertical near-zero stiffness mechanism described in this invention has the following advantages:

[0027] (1) The micro-low gravity field landing simulation test device based on a vertical near-zero stiffness mechanism described in this invention is particularly suitable for landing buffer ground tests of lunar, Martian and other asteroid probes. It provides a fully realistic full-physics simulation simulator test for landing buffer of active soft landing, filling a technical gap in my country's active soft landing test of space probes.

[0028] (2) The micro-low gravity field landing simulation test device based on the vertical near-zero stiffness mechanism described in this invention can realize the combined speed simulation landing under horizontal and vertical speeds. In particular, for the landing buffer of the active legs, it can realize high impact, high dynamic, high precision, and long stroke landing buffer following, and realize the landing buffer of the simulator active legs for soft landing.

[0029] (3) The micro-low gravity field landing simulation test device based on a vertical near-zero stiffness mechanism described in this invention adopts a combination of a two-stage air-floating platform and an accompanying vehicle to achieve passive following at horizontal speed. While releasing the simulator's degrees of freedom, it also solves the interference caused by insufficient following control accuracy of the accompanying vehicle. Attached Figure Description

[0030] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0031] Figure 1 This is a schematic diagram of the micro-low gravity field landing simulation test device based on a vertical near-zero stiffness mechanism as described in an embodiment of the present invention;

[0032] Figure 2 This is a schematic diagram of the experimental principle of the micro-low gravity field landing simulation test device based on a vertical near-zero stiffness mechanism as described in an embodiment of the present invention.

[0033] Explanation of reference numerals in the attached figures:

[0034] 1. Truss; 2. Linear module; 3. Electromagnet; 4. Detector simulator; 5. Zero-stiffness mechanism; 6. Accompanying vehicle; 7. Simulated star catalog. Detailed Implementation

[0035] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other.

[0036] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, the terms "first," "second," etc., 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 with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0037] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art will understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0038] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0039] A micro-low gravity field landing simulation test device based on a vertical near-zero stiffness mechanism 5, such as Figures 1-2 As shown, it includes truss 1, linear module 2, electromagnet 3, probe simulator, zero stiffness mechanism 5, accompanying vehicle 6, and simulated star table 7; to realize ground verification test of probe landing buffer landing, especially covering the hard landing of passive legs and the soft landing of active legs on the ground test verification work.

[0040] The truss 1 is mounted on the simulated star catalog 7. A guide rail is laid in the middle of the simulated star catalog 7. A linear module 2 is mounted on the truss 1 directly above the guide rail. An electromagnet 3 is mounted on the moving block of the linear module 2. The linear module 2 can be connected to the detection simulator through the electromagnet 3.

[0041] The detection simulator is mounted to the accompanying vehicle 6 via a zero-stiffness mechanism 5, and the accompanying vehicle 6 is capable of moving on the runway.

[0042] Preferably, the truss 1 is constructed from a ball-and-stick mechanism and connected to the linear module 2. The simulator is connected to the truss 1 structure to realize the landing buffer conditions of horizontal acceleration and vertical descent. Its structure has good stability and can withstand tons of weight.

[0043] Preferably, the linear module 2 is connected to the truss 1 structure to provide horizontal speed for the detection simulator. When there is no horizontal speed, the linear module 2 does not need to move and releases the electromagnet 3 in place to obtain vertical speed. When there is both horizontal and vertical speed, the linear module 2 drives the detector simulator 4 to move and releases the electromagnet 3 after reaching the predetermined horizontal speed.

[0044] Preferably, the electromagnet 3 serves as a connection between the linear module 2 and the detector simulator 4. The switching on and off of the electromagnet 3 can realize the release and fall of the simulator. When there is horizontal and vertical speed, the automatic switching on and off of the electromagnet 3 is controlled by detecting the horizontal speed of the module.

[0045] Preferably, the detection simulator includes a simulator frame, an air-bearing ball bearing, a planar air cushion, an air-bearing platform, and landing legs. The detection simulator needs to simulate the mass and inertia of a real detector, as well as the release of six degrees of freedom. The air-bearing ball bearing releases three rotational degrees of freedom, the planar air cushion slides on the small platform, releasing two translational degrees of freedom, and the vertical degree of freedom is realized by the zero-stiffness mechanism 5. This simulates a real landing load for the landing legs, making the simulation effect more realistic and effective.

[0046] Preferably, the zero-stiffness mechanism 5 includes a magnetostrictive zero-stiffness mechanism and a servo servo actuator. The magnetostrictive zero-stiffness mechanism is composed of an electromagnet 3 and other structures. This structure can maintain a constant force value within a range of ±5mm. Therefore, during the landing process of the probe simulator 4, facing the highly dynamic landing characteristics, the magnetostrictive zero-stiffness mechanism is a purely passive approach and can follow the high-impact, short-stroke landing motion characteristics in a timely manner. The servo actuator is composed of a lead screw, a motor, etc. During the landing process of the probe simulator, landing buffering is required, and the buffering stroke is relatively large. The stroke of the magnetostrictive zero-stiffness mechanism alone is far from sufficient to meet the landing motion requirements. Therefore, a servo servo is connected in series below the magnetostrictive zero stiffness. The position change of the zero stiffness is detected by the grating, and the movement of the servo mechanism is controlled. When the magnetostrictive zero stiffness changes displacement, the servo servo will respond quickly to compensate for the movement during the landing buffer process. The zero stiffness mechanism 5 unloads the weight of the probe simulator 4. When simulating lunar landing, the zero stiffness mechanism 5 needs to bear 5 / 6 of the weight of the simulator 5 to simulate 1 / 6g of gravitational acceleration. The simulation landing method for other extraterrestrial bodies is the same, only the unloading weight of the zero stiffness mechanism 5 needs to be changed.

[0047] Preferably, the accompanying vehicle 6 moves together with the landing simulation device. When the detector only has vertical velocity, the accompanying vehicle 6 does not need to follow; simply releasing the electromagnet 3 at rest is sufficient to achieve a landing buffer at vertical velocity. When there is both horizontal and vertical velocity, the linear module 2 drives the simulator to accelerate horizontally, and the accompanying vehicle 6 follows until the simulator lands and stabilizes, at which point the accompanying vehicle 6 can stop moving. Due to the presence of the air-floating platform, the following accuracy of the accompanying vehicle 6 in the control system can be reduced.

[0048] Preferably, the simulated star surface 7 simulates the surface characteristics of the star surface based on the simulated surface characteristics of extraterrestrial objects, and the star surface characteristics such as pits, bumps and slopes can be realized through design;

[0049] Preferably, the detection simulator simulates the mass and inertia of a real detector, as well as the release of its six degrees of freedom.

[0050] Preferably, the zero-stiffness mechanism 5 can maintain a constant force value within a range of ±5mm.

[0051] The method of using the micro-low gravity field landing simulation test device based on the vertical near-zero stiffness mechanism 5 includes the following steps:

[0052] S1. Assembly of the test device system;

[0053] S2. A landing test is conducted in a low gravity field, taking 1 / 6g on the lunar surface as an example; adjustments are made before the test; the zero stiffness mechanism 5 is adjusted to balance 5 / 6 of the mass of the probe simulator, and the remaining 1 / 6 of the mass is balanced by the suspension force at the top of the probe simulator; the electromagnet 3 is energized, and the linear module 2 is connected to the probe simulator through the electromagnet 3;

[0054] S3, Begin the experiment;

[0055] When there is only vertical velocity, electromagnet 3 is de-energized, and the probe simulator is subjected to an unbalanced 1 / 6g gravity force and undergoes 1 / 6g free fall motion until the probe simulator falls onto the simulated star table 7, completing the landing simulation experiment;

[0056] When there is both horizontal and vertical speed, the linear module 2 drives the probe simulator to move, and the accompanying vehicle 6 follows the movement; when the preset horizontal speed is reached, the electromagnet 3 is de-energized and releases the probe simulator. The probe simulator is affected by 1 / 6g of gravity and accelerates downward by 1 / 6g. By combining with the horizontal speed, the probe simulator moves in a parabolic motion, and the accompanying vehicle 6 always follows the movement until the simulator lands on the simulated star table 7 and the state is stable.

[0057] S4. When simulating microgravity of other extraterrestrial bodies, the supporting force of the zero-stiffness mechanism 5 is adjusted to achieve simulation tests of landing under different gravitational accelerations. The process is the same as the above process.

[0058] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A micro-low gravity field landing simulation test device based on a vertical near-zero stiffness mechanism, characterized in that: This includes trusses, linear modules, electromagnets, detection simulators, zero-stiffness mechanisms, accompanying vehicles, and simulated star catalogs; The truss is mounted on a simulated star catalog, with a guide rail laid in the middle of the catalog. A linear module is mounted on the truss directly above the guide rail. The moving block of the linear module is equipped with an electromagnet, and the linear module can be connected to the detection simulator via the electromagnet. The detection simulator is mounted to the accompanying vehicle via a zero-stiffness mechanism, and the accompanying vehicle is able to move on the guide rail; The accompanying vehicle moves together with the landing simulation device. When the detector only has vertical speed, the accompanying vehicle does not need to follow. It only needs to release the electromagnet at rest to achieve landing buffering at vertical speed. When there is both horizontal and vertical speed, the linear module drives the simulator to accelerate horizontally. At this time, the accompanying vehicle follows until the simulator lands and stabilizes, at which point the accompanying vehicle can stop moving. Due to the presence of the air-floating platform, the following accuracy of the accompanying vehicle in the control system can be reduced. The zero-stiffness mechanism includes a magnetostrictive zero-stiffness actuator and a servo servo actuator. The magnetostrictive zero-stiffness actuator includes an electromagnet. This structure can maintain a constant force value within a range of ±5mm. Therefore, during the landing process of the probe simulator, facing highly dynamic landing characteristics, the magnetostrictive zero-stiffness actuator is a purely passive mechanism that can follow the landing motion characteristics of high impact and short stroke as needed. The servo servo actuator includes a lead screw and a motor. During the landing process of the probe simulator, landing buffering is required. The buffering stroke is relatively large, and the stroke of the magnetostrictive zero-stiffness actuator cannot meet the landing motion characteristics. Therefore, a servo servo actuator is connected in series below the magnetostrictive zero-stiffness actuator. The position change of the zero-stiffness actuator is detected by a grating, and the movement of the servo actuator is controlled. When the magnetostrictive zero-stiffness actuator experiences a displacement change, the servo servo actuator will respond quickly to compensate for the motion stroke during the landing buffering process. The zero-stiffness mechanism unloads the weight of the probe simulator. When simulating lunar landing, the zero-stiffness mechanism needs to bear 5 / 6 of the weight of the simulator to simulate 1 / 6g of gravitational acceleration. The simulated landing method for other extraterrestrial bodies is the same, only the unloading weight of the zero-stiffness mechanism needs to be changed. 2.The micro-low-gravity field landing simulation test device based on the vertical direction near-zero stiffness mechanism of claim 1, wherein: The detection simulator simulates the size, mass, and inertia of a real detector, as well as the release of its six degrees of freedom. 3.The micro-low-gravity field landing simulation test device based on the vertical direction near-zero rigidity mechanism of claim 1, wherein: The zero-stiffness mechanism can maintain a constant force value within a range of ±5mm.

4. The method of using the micro-low gravity field landing simulation test device based on a vertical near-zero stiffness mechanism according to any one of claims 1-3, characterized in that: Includes the following steps: S1. Assembly of the test device system; S2. Pre-test adjustment: Adjust the zero-stiffness mechanism to balance 5 / 6 of the mass of the detection simulator, with the remaining 1 / 6 of the mass balanced by the suspension force at the top of the detection simulator; energize the electromagnet, and connect the linear module to the detection simulator through the electromagnet. S3, Begin the experiment; When there is only vertical velocity, the electromagnet is de-energized, and the probe simulator is subjected to an unbalanced 1 / 6g gravity force and undergoes 1 / 6g free fall motion until the probe simulator falls onto the simulated star table, completing the landing simulation experiment; When there is both horizontal and vertical speed, the linear module drives the probe simulator to move, and the accompanying vehicle follows the movement; when the preset horizontal speed is reached, the electromagnet is de-energized and the probe simulator is released. The probe simulator is affected by 1 / 6g of gravity and accelerates downward by 1 / 6g. By combining with the horizontal speed, the probe simulator moves in a parabolic motion, and the accompanying vehicle always follows the movement until the simulator lands on the simulated star table and the state is stable. S4. When simulating microgravity of other extraterrestrial bodies, the landing simulation test under different gravitational accelerations is achieved by adjusting the support force of the zero-stiffness mechanism. The process is the same as the above process.

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