Suspension type micro-low gravity simulation device and method based on rear quasi-zero stiffness unit

Abstract

The invention belongs to the technical field of aerospace engineering, and relates to a suspension type micro-low gravity simulation device and method based on a rear quasi-zero stiffness unit. The device comprises a quasi-zero stiffness supporting assembly and a suspension assembly. The quasi-zero stiffness supporting assembly comprises a bottom plate, a bearing plate, a positive stiffness elastic adjusting module, a magnetic negative stiffness module, a guide mechanism and a displacement sensing unit, wherein the positive stiffness elastic adjusting module, the magnetic negative stiffness module, the guide mechanism and the displacement sensing unit are arranged between the bottom plate and the bearing plate. The magnetic negative stiffness module and the positive stiffness elastic adjusting module are located on the two sides of the guide mechanism and can stretch out and draw back. The rigidity of the positive rigidity elastic adjusting module is larger than the absolute value of the rigidity of the magnetic negative rigidity module, so that the quasi-zero rigidity supporting assembly has the positive rigidity characteristic. The suspension assembly comprises a motor and a suspension unit which are connected, the motor is connected with an external control unit, and the tail end of the suspension unit is used for suspending a simulation object; and the external control unit can regulate and control the motor based on the relative displacement, so that the supporting force of the quasi-zero-stiffness supporting assembly on the suspension assembly is kept constant. According to the invention, a high-fidelity micro-low gravity simulation test in a large stroke can be realized.

Description

Technical Field

[0001] This application belongs to the field of aerospace engineering technology, and more specifically, relates to a suspended micro-low gravity simulation device and method based on a post-positioned quasi-zero stiffness element. Background Technology

[0002] When spacecraft operate in the microgravity environment of space or other celestial bodies, their mechanical properties and control systems may face unpredictable disturbances. To ensure the safe and stable execution of space missions, it is necessary to simulate microgravity environments on the ground to verify and optimize spacecraft performance.

[0003] Currently, the mainstream methods for simulating microgravity include free fall, suspension, support, and water flotation. Among these, the suspension method based on a pendulum mechanism and the support method based on an air-floating platform can perform long-duration simulations of large-volume, large-mass objects, requiring less experimental space and lower cost, thus meeting laboratory needs and having a wider range of applications. Both the suspension and support methods primarily aim to unload gravity in the vertical direction, and each has its own advantages and limitations.

[0004] Suspension methods, as the mainstream approach for spacecraft attitude change testing, offer significant advantages over support methods: smaller added mass, higher degrees of freedom for the simulated object, and easier integration with horizontal vibration reduction systems, thus facilitating subsequent research. Based on different force compensation mechanisms, suspension methods can be broadly categorized into passive and active suspension methods. Passive suspension methods mainly include counterweight balancing, inclined plane suspension, and constant force spring suspension; active suspension methods encompass servo motor force-controlled suspension, constant force cylinder suspension, and electromagnetic active suspension. In particular, servo motor force-controlled suspension has become the preferred option due to its high precision and rapid response. However, existing experimental setups still suffer from several technical limitations: firstly, the suspension mechanism itself introduces parasitic torque interference; secondly, system performance is limited by the measurement accuracy of the force sensors. These inherent defects restrict the further application of this method in high-precision microgravity simulation.

[0005] Therefore, a position-controlled, high-precision, and high-response-speed suspended microgravity simulation device and experimental method are needed. Summary of the Invention

[0006] To address the shortcomings of existing technologies, the purpose of this application is to provide a suspended microgravity simulation device and method based on a post-positioned quasi-zero stiffness element, aiming to solve the problems of introducing parasitic torque interference and the limitation of system performance on the measurement accuracy of force sensors in existing suspended microgravity simulation technologies.

[0007] To achieve the above objectives, in a first aspect, this application provides a suspended micro-low gravity simulation device based on a rear-mounted quasi-zero stiffness unit, comprising a quasi-zero stiffness support assembly and a suspension assembly, wherein: the quasi-zero stiffness support assembly includes a base plate and a load-bearing plate, and a positive stiffness elastic adjustment module, a magnetic negative stiffness module, a guide mechanism, and a displacement sensing unit respectively disposed between the two; the magnetic negative stiffness module and the positive stiffness elastic adjustment module are located on both sides of the guide mechanism, and both can extend and retract in the vertical direction to change the distance between the base plate and the load-bearing plate; the stiffness of the positive stiffness elastic adjustment module is greater than that of the magnetic negative stiffness module. The stiffness absolute value of the stiffness module is used to make the quasi-zero stiffness support assembly exhibit positive stiffness characteristics; the suspension assembly includes a motor and a suspension unit, the motor is mounted on the load-bearing plate, and its output end is connected to the suspension unit, the end of the suspension unit is used to suspend the simulated object; the displacement sensing unit can detect the relative displacement between the base plate and the load-bearing plate and transmit it to the external control unit, the external control unit can adjust the speed or torque of the motor based on the relative displacement, so that the relative displacement between the base plate and the load-bearing plate approaches 0, thereby keeping the supporting force of the quasi-zero stiffness support assembly on the suspension assembly constant.

[0008] Furthermore, the positive stiffness elastic adjustment module includes a positive stiffness spring and a spring preload mechanism. The spring preload mechanism is connected to the base plate, one end of the positive stiffness spring is connected to the load-bearing plate, and the other end is connected to the spring preload mechanism.

[0009] Furthermore, the positive stiffness spring and the magnetic negative stiffness module are connected in parallel and arranged in parallel with each other.

[0010] Furthermore, the magnetic negative stiffness module includes a stator and a mover coaxially mounted, with the stator fixed to the load-bearing plate and the mover fixed to the base plate.

[0011] Furthermore, the suspension assembly also includes a winch mechanism and a drum. The winch mechanism is connected to the output shaft of the motor. The drum is mounted on the output end of the winch mechanism, and the suspension unit is wound around the drum. When the motor rotates, it can drive the winch mechanism to rotate, thereby driving the drum to retract and extend the suspension unit.

[0012] Furthermore, the suspension unit is a steel wire rope, and a rope guide is coaxially mounted on the outside of the drum for guiding the steel wire rope.

[0013] Furthermore, a spiral guide groove is provided on the surface of the drum, and the steel wire rope is wound in the spiral guide groove.

[0014] Furthermore, the simulated object is located below the base plate.

[0015] Furthermore, the suspension unit is connected to the simulated object via an elastic element; and / or, the elastic element is a metal spring with a stiffness of 0.51 N / mm to 1 N / mm and a mass of no more than 10 g.

[0016] Secondly, a method for simulating a microgravity environment using the suspended microgravity simulation device as described above is provided, including: S1 fixes the suspended micro-low gravity simulation device to the external frame in the surface gravity environment, and suspends the simulated object at the end of the suspension unit. S2 unlocks the guide mechanism to release its vertical degree of freedom, allowing the quasi-zero stiffness support assembly to move only vertically; S3 adjusts the positive stiffness elastic adjustment module to raise the load-bearing plate so that the positive stiffness elastic adjustment module provides full support force, thereby enabling the simulated object to reach static equilibrium under the gravitational field. S4 continues to adjust the positive stiffness elastic adjustment module to make the load-bearing plate rise continuously until the magnetic negative stiffness module in static equilibrium works near the design zero point. S5 applies an external force vertically to the simulated object to generate instantaneous acceleration. The tension of the suspension unit changes abruptly under the action of instantaneous acceleration, causing a change in the horizontal height of the load-bearing plate and the motor. The displacement sensing unit collects the relative displacement of the load-bearing plate relative to the base plate and transmits it to the external control unit. The external control unit can adjust the speed or torque of the motor based on the relative displacement so that the relative displacement between the base plate and the load-bearing plate approaches 0, thereby keeping the support force of the quasi-zero stiffness support assembly on the suspension assembly constant.

[0017] Overall, the technical solutions conceived in this application have the following beneficial effects compared with the prior art: (1) The base plate of the quasi-zero stiffness support assembly of this application is rigidly connected to the external fixed frame, and the load-bearing plate is reliably connected to the suspension assembly through a mechanical interface; the simulated object is elastically suspended through the suspension unit. The quasi-zero stiffness assembly realizes the vertical gravity unloading of the load and the additional mass module, and the suspension assembly, while ensuring the vertical motion trajectory of the simulated object, works with the quasi-zero stiffness support assembly to perform more precise gravity unloading. The motor in the suspension assembly is connected to the external main control equipment, and the deformation of the quasi-zero stiffness support assembly is adjusted to zero by controlling the speed of the motor, thereby ensuring constant tension of the suspension cable, thus simulating the dynamic behavior of the simulated object under micro-low gravity environment.

[0018] (2) This application connects the positive stiffness elastic adjustment module and the magnetic negative stiffness module in parallel, and makes the positive stiffness slightly greater than the absolute value of the negative stiffness, so that the overall system forms a range with extremely low stiffness (close to zero) near the equilibrium point. When the suspended simulated object (such as a spacecraft component) undergoes a small vertical displacement or is disturbed, the supporting force provided by this device changes extremely little. This makes the vertical constraint force felt by the suspended object very "soft" and constant, more accurately simulating the state of the supporting force on an object in the microgravity environment of space, which is almost constant (or changes very little), and overcomes the force fluctuation problem caused by the large stiffness of traditional spring or constant force suspension wire systems.

[0019] (3) The quasi-zero stiffness support component of this device has an extremely low natural frequency, which can significantly shift the starting vibration isolation frequency of the entire system to a lower frequency. Therefore, it can passively and efficiently isolate low-frequency, large-amplitude vibration interference from the base plate, providing a quieter and more stable reference platform for microgravity simulation.

[0020] (4) In this application, the closed-loop active control system consisting of the displacement sensing unit and the external control unit in the quasi-zero stiffness component serves as a "fine-tuning" link. The displacement sensing unit detects the relative displacement between the base plate and the load-bearing plate caused by the residual force that cannot be completely offset by the quasi-zero stiffness. The external control unit quickly drives the motor to adjust the tension or extension / retraction length of the suspension unit, making the relative displacement approach zero. By maintaining a constant relative position between the load-bearing plate and the base plate, the support force height of the suspension point on the simulated object is indirectly ensured to be constant, realizing high-precision dynamic simulation of microgravity (or specific low gravity) environments. It compensates for deviations and high-frequency disturbances outside the quasi-zero stiffness range and has a fast response speed.

[0021] (5) The negative stiffness module of this application typically changes the negative stiffness value by adjusting the relative position or current of the permanent magnet or electromagnet. The stiffness of the positive stiffness elastic adjustment module is also adjustable. By adjusting both, the quasi-zero stiffness characteristics of the system can be achieved within a wide load range (adapting to simulated objects of different weights), improving the versatility and adaptability of the device. Compared with mechanical springs with fixed parameters, the flexibility is greatly improved.

[0022] (6) This application achieves high-precision and high-stability dynamic simulation of micro-low gravity through a two-step method of "passive balancing followed by active following". First, by adjusting the positive stiffness module, the magnetic negative stiffness unit is made to work precisely near the "quasi-zero point". Its passive near-zero stiffness characteristics are used to absorb most of the static load and low-frequency disturbances, laying the foundation for low dynamic coupling of the system. Active control is only activated when the passive balance is briefly broken (such as when an external force is applied). The motor is quickly driven to compensate through displacement feedback, so that the system can quickly return to force balance. In addition, the simulation method of this application combines the stability and reliability of the passive system with the high precision of the active system. It significantly reduces the bandwidth and energy consumption requirements of pure active control, while avoiding the disadvantages of slow response and poor anti-interference of pure passive system. It is especially suitable for simulating scenarios with instantaneous force impacts, such as spacecraft on-orbit operation and docking. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the suspended micro-low gravity simulation device with a rear-mounted quasi-zero stiffness unit provided in Embodiment 1 of this application; Figure 2 This is a comparative schematic diagram of the pre-quasi-zero stiffness element and the post-quasi-zero stiffness element provided in Embodiment 1 of this application; Figure 3 This is a force diagram of the suspended micro-low gravity simulation device provided in Embodiment 1 of this application; Figure 4 This is a schematic diagram of the suspended micro-low gravity simulation device with a rear-mounted quasi-zero stiffness unit provided in Embodiment 2 of this application; Figure 5 This is a schematic diagram of the process of simulating a micro-low gravity environment using a suspended micro-low gravity simulation device with a post-positioned quasi-zero stiffness unit, as provided in Embodiment 3 of this application.

[0024] In all the accompanying drawings, the same reference numerals are used to denote the same elements or structures, wherein: 1-Base plate, 2-Positive stiffness spring, 3-Bearing plate, 4-Displacement sensing unit, 5-Guiding mechanism, 6-Winding mechanism, 7-Rope arranger, 8-Drum, 9-Motor, 10-Magnetic negative stiffness module, 101-Stator, 102-Motor, 11-Spring pretensioning mechanism, 12-Wire rope, 13-Simulated object, 14-Elastic element. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0026] In the description of the embodiments of this application, unless otherwise stated, "multiple" means two or more, for example, multiple processing units means two or more processing units, multiple elements means two or more elements, etc.

[0027] The embodiments of this application are described below with reference to the accompanying drawings.

[0028] Example 1 This embodiment provides a suspended micro-low gravity simulation device based on a post-positioned quasi-zero stiffness element, such as... Figure 1 As shown, it includes a quasi-zero stiffness support assembly and a suspension assembly, wherein: the quasi-zero stiffness support assembly includes a base plate 1 and a load-bearing plate 3 arranged in parallel, and a positive stiffness elastic adjustment module, a magnetic negative stiffness module 10 and a guide mechanism 5 respectively arranged between the two and fixedly connected to the two, and a displacement sensing unit 4 connected to the load-bearing plate 3.

[0029] The aforementioned magnetic negative stiffness module 10 and positive stiffness elastic adjustment module are located on both sides of the guide mechanism 5, and both can extend and retract in the vertical direction to change the distance between the base plate 1 and the load-bearing plate 3. Furthermore, the stiffness of the positive stiffness elastic adjustment module is greater than the absolute value of the stiffness of the magnetic negative stiffness module 10, so that the quasi-zero stiffness support assembly exhibits positive stiffness characteristics.

[0030] The aforementioned suspension assembly includes at least a motor 9 and a suspension unit. The motor 9 is mounted on the outer side of the load-bearing plate 3, and its output end is connected to the suspension unit. The end of the suspension unit is located below the base plate 1 and is used to suspend the simulated object 13, ensuring that the simulated object 13 is also located below the base plate 1. The displacement sensing unit 4 can detect the relative displacement between the base plate 1 and the load-bearing plate 3 and transmit it to an external control unit. The external control unit can adjust the speed or torque of the motor 9 based on the relative displacement to make the relative displacement between the base plate 1 and the load-bearing plate 3 approach 0, thereby keeping the supporting force of the quasi-zero stiffness support assembly on the suspension assembly constant.

[0031] In this embodiment, the quasi-zero stiffness support assembly and the suspension assembly are connected in a rear-mounted manner, combined with... Figure 2 As shown, the left figure is a schematic diagram of the front-mounted connection method, which shows the connection sequence of load-quasi-zero stiffness support assembly-motor. The right figure is a schematic diagram of the rear-mounted connection method, which shows the connection sequence of load-motor-quasi-zero stiffness support assembly. In this embodiment, the connection sequence of each module of the rear-mounted suspension structure is: foundation-quasi-zero stiffness support assembly-motor-suspension unit-simulation object 13, that is, the quasi-zero stiffness support assembly is installed between the motor and the foundation.

[0032] In this embodiment, the aforementioned guiding mechanism 5 is used to achieve frictionless relative motion and constrain other degrees of freedom except for the vertical direction. Specifically, the guiding mechanism 5 can be an air-bearing guide rail, a leaf spring guiding mechanism, a mechanical guide rail, a linkage mechanism with guiding function, etc. Air-bearing guide rails are the best choice, as they can achieve truly frictionless, high-precision linear guidance, with no wear and a long service life. Precision crossed roller guide rails are the second choice; although there is micron-level friction, they have good rigidity and strong load-bearing capacity. Leaf spring guiding mechanisms are completely frictionless and have no backlash, but their stroke is limited. All guiding mechanisms must be equipped with mechanical limit blocks (such as polyurethane buffers installed at both ends of the guide rail) and have manual locking screws in the non-working state to prevent the load-bearing plate 3 from accidentally moving and damaging components during transportation and installation. The limiting and locking mechanisms can constrain the stroke of the guiding mechanism 5 and limit the degrees of freedom of the guiding mechanism 5 in the non-working state.

[0033] In this embodiment, the aforementioned positive stiffness elastic adjustment module includes a positive stiffness spring 2 and a spring preload mechanism 11. One end of the positive stiffness spring 2 is connected to the load-bearing plate 3, and the other end is connected to the spring preload mechanism 11. The other end of the spring preload mechanism 11 is connected to the base plate 1. It can provide a large load-bearing capacity while achieving quasi-zero stiffness characteristics and maintaining frictionless movement.

[0034] Specifically, the aforementioned positive stiffness spring 2 and magnetic negative stiffness module 10 are connected in parallel and arranged in parallel with each other, so that the magnetic negative stiffness module 10 and the positive stiffness elastic adjustment module form a quasi-zero stiffness elastic component to support the mass of the simulated load. The load-bearing capacity of the positive stiffness elastic adjustment module must exceed the gravity load of the simulated object, while the absolute value of the stiffness of the magnetic negative stiffness module 10 should be slightly less than the stiffness of the positive stiffness spring 2, to ensure that the quasi-zero stiffness elastic component exhibits a small positive stiffness characteristic. The spring preload mechanism 11 can adjust the installation height of the positive stiffness spring 2 according to the load mass and the requirements of the simulated gravity environment, achieving adaptive adjustment under different working conditions.

[0035] More specifically, the positive stiffness spring 2 can be a metal coil spring, a hydraulic support mechanism, or a pneumatic support mechanism. In this embodiment, a high-performance metal coil spring is preferred due to its high stiffness linearity and good stability. For other scenarios requiring dynamic adjustment of preload, a pneumatic support mechanism can be used, achieving stepless and rapid adjustment of the support force through a precision pneumatic servo valve. A hydraulic support mechanism is suitable for extremely heavy load conditions, but oil sealing and temperature drift issues need to be considered.

[0036] The aforementioned displacement sensing unit 4 is responsible for real-time monitoring of the relative displacement changes between the base plate 1 and the load-bearing plate 3. The guide mechanism 5 isolates the magnetic negative stiffness module 10 from the positive stiffness elastic adjustment module. Under the condition of releasing the vertical degree of freedom, since the guide mechanism 5 is vertically set between the base plate 1 and the load-bearing plate 3 and is fixedly connected to the base plate 1 and the load-bearing plate 3 respectively, when an instantaneous external force is applied, the guide mechanism 5 extends and retracts in the vertical direction. The base plate 1 and the load-bearing plate 3 also move closer or further away in the vertical direction under the limiting action of the guide mechanism 5. That is, the guide mechanism 5 plays a guiding role in the vertical direction (i.e., vertical direction) of the movement of the two, ensuring that the entire simulation device achieves frictionless movement in the direction of gravity, thereby ensuring that the relative displacement signal detected by the displacement sensing unit 4 can be accurately converted into the torque output of the motor 9.

[0037] Specifically, the displacement sensing unit 4 can be selected as a grating ruler displacement sensor, a laser displacement sensor, or a capacitive displacement sensor; if a grating ruler displacement sensor is selected, the guide structure 5 is also provided with a support structure 51 for fixing it.

[0038] In this embodiment, the magnetic negative stiffness module 10 includes a stator 101 and a mover 102 coaxially mounted. The stator 101 is fixed to the load-bearing plate 3, and the mover 102 is fixed to the base plate 1. Specifically, the stator 101 is columnar, and the mover 102 is a cylindrical structure with an internal sliding cavity. The movable end of the stator 101 can move up and down with the load-bearing plate within the sliding cavity of the mover 102.

[0039] Specifically, the magnetic negative stiffness module 10 can also be selected as a magnetic negative stiffness mechanism, a buckling beam negative stiffness unit, or a link-spring negative stiffness mechanism. However, the buckling beam (pre-compressed buckling slender rod) negative stiffness unit scheme has a compact structure, but its load capacity is low and it has stability problems. The link-spring negative stiffness mechanism can generate negative stiffness through clever mechanism design, but it may introduce friction and gaps. Therefore, in this embodiment, a permanent magnet negative stiffness mechanism is preferred, which uses the repulsive field of like poles relative to each other permanent magnets to generate negative stiffness characteristics, without contact, friction, or energy consumption. Specifically, a ring magnet or a square magnet pair can be used, one as the stator and the other as the mover, and a precision guide rail design is used to ensure the magnetic pole alignment, ensuring the linearity and repeatability of the force-displacement characteristics.

[0040] In this embodiment, the suspension assembly also includes a winch mechanism 6 and a drum 8. The winch mechanism 6 is connected to the output shaft of the motor 9. The drum 8 is installed on the output end of the winch mechanism 6, and the suspension unit is wound around the drum 8. When the motor 9 rotates, it can drive the winch mechanism 6 to rotate, thereby driving the drum 8 to retract and extend the suspension unit.

[0041] Specifically, a rope guide 7 is coaxially mounted on the outside of the drum 8, and the suspension unit is a steel wire rope 12. The rope guide 7 is used to guide the steel wire rope 12.

[0042] More specifically, the surface of the drum 8 is provided with a spiral guide groove, and the wire rope 12 is wound in the spiral guide groove to achieve precise winding and release, avoiding tangled ropes or rope overlap.

[0043] The main control device (i.e., external control unit) of the aforementioned motor 9 receives the relative displacement signal fed back by the displacement sensing unit 4 and controls and adjusts the torque or speed of the motor 9 to ensure that the relative displacement between the base plate 1 and the load-bearing plate 3 is constant. This makes the deformation of the positive stiffness elastic adjustment module close to zero, thereby ensuring that the support force fluctuation of the load-bearing plate 3 on the suspension component is close to zero, while ensuring that the movement trajectory of the wire rope 12 and the simulated object 13 is smooth. The wire rope guide 7 is coaxially mounted on the outside of the drum 8 to guide the wire rope 12, ensuring that there is no tangled rope or overlapping of the ropes.

[0044] In this embodiment, the control of the zero-gravity simulation system with a rear-mounted elastic element suspension is a servo-driven control of motor 9. The servo control of motor 9 aims to release vertical degrees of freedom by rapidly responding to the vertical motion of the experimental object. The displacement sensing unit 4 collects position change information of the experimental object, and the external control unit controls motor 9 to adjust its torque or speed through position feedback, achieving servo-driven control of the load.

[0045] The following is combined with Figure 3 This explains the working principle of this embodiment.

[0046] The mass of the simulated object 13 is M The additional mass (including load-bearing plate 3, motor 9, wire rope 12, and fixed parts) is M’ The vertical stiffness value of the quasi-zero stiffness support assembly is k The damping of the quasi-zero stiffness support assembly is c The torsional radius of motor 9 is r The gravitational acceleration of Earth under experimental conditions is g The quasi-zero stiffness unit consists of a positive stiffness element 2 and a magnetic negative stiffness module 10. The stiffness of the magnetic negative stiffness module 10 is designed to be... k n .according to k n Select or manufacture a positive stiffness element 2 with suitable stiffness, and the stiffness of positive stiffness element 2... k p Slightly larger in numerical value k n Make the vertical stiffness k of the quasi-zero stiffness support assembly = k n +k p It is a positive value close to 0. In this embodiment, when the device is in operation and in a static state, the supporting force provided by the quasi-zero stiffness support assembly is:

[0047] The purpose of the above formula is to balance gravity.

[0048] When the simulated object 13 accelerates at the desired constant speed During movement, the steel wire rope 12 will ideally provide a constant tension:

[0049] The aforementioned tension can be converted into a constant torque provided by motor 9. The relative height between the base plate 1 and the load-bearing plate 3 at this time is x0. When the simulated object 13 is subjected to an external force... F ext At the instant the state changes from static to dynamic, due to the sudden change in tension in the wire rope 12, the horizontal height of the added mass module will change. This change is calculated as... The instantaneous acceleration of the added mass module is denoted as... The instantaneous acceleration generated by motor 9 is denoted as The instantaneous acceleration generated by the simulated object 13 is denoted as Assuming that wire rope 12 is a rigid rope, the following equation holds:

[0050]

[0051] From the derivation of the dynamic formula of the spring-damped system, we can see that:

[0052] in, F m Let be the inertial reaction force experienced by the additional mass module, and:

[0053] By combining the above equations and performing a Laplace transform, we can obtain the motor's 9-turn angle. and Transfer function between G (s) for:

[0054] in, Δx (s) Let be the height variation in the s-domain (i.e., the complex frequency domain). θ (s) This represents the motor rotation angle in the s-domain. Simultaneously, the input speed of motor 9 can be obtained through calculation. and The transfer function between them is G’(s) for:

[0055] in, Let be the motor speed in the s-domain.

[0056] Therefore, the relative displacement of the positive magnetic stiffness module 10 can be controlled to approach zero by adjusting the speed of motor 9 through the main control device (i.e., the external control unit). Variation of bearing force in quasi-zero stiffness support assembly ,because k When the value approaches zero, the supporting force provided by the quasi-zero stiffness support assembly converges to the ideal value. Simultaneously, the tension of the steel wire rope 12 counteracts the gravity of the simulated object 13, meaning the acceleration of the simulated object 13 is entirely provided by external forces.

[0057] Therefore, the simulated object 13 can approximately achieve the ideal dynamic behavior under zero gravity.

[0058] Example 2 The suspended microgravity simulation device provided in this embodiment is as follows: Figure 4 As shown, the difference between this embodiment and Embodiment 1 is that the suspension unit and the simulated object 13 are connected by an elastic element 14; and the elastic element 14 is a metal spring with a stiffness of 0.5~1N / mm, such as 0.6N / mm, 0.7N / mm, 0.8N / mm, 0.9N / mm or any stiffness value between any two of the aforementioned values, and its mass is not greater than 10g, such as 9g, 8g, 7g, 6g, 5g, 4g or any stiffness value between any two of the aforementioned values, or any mass value less than 4 but greater than 0.

[0059] Specifically, this design ensures that when the simulated object 13 is subjected to external force... F ext When it acts, its instantaneous acceleration Closer to the ideal value Instead of Example 1 The low-stiffness metal spring introduced in this embodiment essentially adds a mechanical low-pass filter between the motor 9 and the simulated object 13. Its function is to decouple high-frequency, small-amplitude disturbances. Although the response of the motor 9 control loop is fast, there are still slight delays and jitters. This buffer spring can absorb these high-frequency, undesirable small excitations transmitted to the simulated object 13, while simultaneously transmitting steady-state, large-amplitude motion, thereby further improving the dynamic fidelity of the simulated object 13 in the high-frequency range. The selection of the spring's stiffness and mass control are crucial and were determined through dynamic simulation optimization. By introducing a spring buffer mechanism, the system can effectively suppress the influence of added mass on the dynamic characteristics of the simulated object 13, especially under sudden external force conditions, significantly improving the consistency between the acceleration response of the simulated object 13 and the ideal acceleration in a micro-low gravity environment.

[0060] Example 3 This embodiment provides a method for simulating a micro-low gravity environment using a suspended micro-low gravity simulation device as described in Embodiment 1. Figure 5 As shown, the method includes the following steps: S1 fixes the suspended micro-low gravity simulation device to the external frame in the surface gravity environment, and suspends the simulation object 13 at the end of the suspension unit; that is, the suspension component is fixedly connected to the load-bearing plate 3, and the motor 9 is connected to the external control unit.

[0061] S2 unlocks the guide mechanism 5 to release its vertical degree of freedom, allowing the quasi-zero stiffness support assembly to move only vertically; that is, unlocks the limiting and locking mechanism of the guide mechanism 5, releasing the vertical degree of freedom of the guide mechanism 5. The guide mechanism 5 is connected to the support plate 3 and the base plate 1 respectively, which enables the quasi-zero stiffness support assembly to move vertically without being affected by frictional forces due to interference from other structural units, while limiting the degree of freedom of the quasi-zero stiffness support assembly to vertical movement.

[0062] S3 adjusts the positive stiffness elastic adjustment module, causing the load-bearing plate 3 to rise, so that the positive stiffness elastic adjustment module provides all the supporting force, thereby allowing the simulated object 13 to reach static equilibrium under the gravitational field; that is, adjusting the spring preload mechanism 11 causes the load-bearing plate 3 to rise slowly, ensuring that all the supporting force is provided by the positive stiffness elastic adjustment module, so that the supporting force of the positive stiffness elastic adjustment module is... This allows the load to be simulated to reach static equilibrium under a gravitational field.

[0063] S4 continues to adjust the positive stiffness elastic adjustment module to continuously raise the load-bearing plate 3 until the magnetic negative stiffness module 10 in static equilibrium works near the design zero point.

[0064] After the equipment stabilizes, the simulation test begins. An external force is applied vertically to the simulated object 13 to generate instantaneous acceleration. The tension of the suspension unit changes abruptly under the action of instantaneous acceleration, causing a change in the horizontal height of the load-bearing plate 3 and the motor 9. The displacement sensing unit 4 collects the relative displacement of the load-bearing plate 3 relative to the base plate 2 and transmits it to the external control unit. The external control unit can adjust the torque (or speed) of the motor 9 based on the relative displacement so that the relative displacement between the base plate 1 and the load-bearing plate 3 approaches 0, thereby keeping the support force of the quasi-zero stiffness support assembly on the suspension assembly constant.

[0065] As can be seen from the derivation of the transfer function in Example 1, by adjusting the torque of motor 9, the height change of the positive stiffness elastic adjustment module converges to zero in a short time, thus providing a change in support force. The tension approaches zero, thus ensuring that the horizontal position of the motor remains constant at any given moment during the simulation period, and the tension in the wire rope satisfies... The acceleration of the simulated object is entirely provided by external forces, that is... At this point, the simulated object on the Earth's surface exhibits dynamic behavior that is precisely consistent with its behavior in a zero-gravity environment under the influence of Earth's gravity and the pulling force of the microgravity environment simulation device.

[0066] It is understood that the various numerical designations used in the embodiments of this application are merely for the convenience of description and are not intended to limit the scope of the embodiments of this application.

[0067] It should be understood that expressions such as “comprising” and “may include” used in this application indicate the existence of the disclosed functions, operations, or constituent elements, and do not limit one or more additional functions, operations, and constituent elements. In this application, terms such as “comprising” and / or “having” are to be interpreted as indicating a particular characteristic, number, operation, constituent element, component, or combination thereof, but not to exclude the existence or possibility of adding one or more other characteristics, numbers, operations, constituent elements, components, or combinations thereof.

[0068] Furthermore, in this application, the expression "and / or" includes any and all combinations of the associated listed words. For example, the expression "A and / or B" may include A, may include B, or may include both A and B.

[0069] In the description of the embodiments of this application, it should be noted that, unless otherwise explicitly specified and limited, the term "connection" should be interpreted broadly. For example, "connection" can be a detachable connection or a non-detachable connection; it can be a direct connection or an indirect connection through an intermediate medium. "Fixed connection" refers to a connection where the relative positional relationship remains unchanged after connection. "Rotary connection" refers to a connection where the components can rotate relative to each other after connection. "Sliding connection" refers to a connection where the components can slide relative to each other after connection. The directional terms mentioned in the embodiments of this application, such as "top," "bottom," "inner," "outer," "left," and "right," are only for reference to the directions in the accompanying drawings. Therefore, the directional terms used are for better and clearer explanation and understanding of the embodiments of this application, and are not intended to indicate or imply that the device or component referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of this application.

[0070] Furthermore, the mathematical concepts mentioned in the embodiments of this application, such as symmetry, equality, parallelism, and perpendicularity, are limitations specific to the current technological level, rather than absolute and strict mathematical definitions. Slight deviations are permissible; approximations of symmetry, equality, parallelism, and perpendicularity are all acceptable. For example, "A and B are parallel" means that A and B are parallel or approximately parallel, and the angle between A and B can be between 0 and 10 degrees. "A and B are perpendicular" means that A and B are perpendicular or approximately perpendicular, and the angle between A and B can be between 80 and 100 degrees.

[0071] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A suspended micro-low gravity simulation device based on a post-positioned quasi-zero stiffness element, characterized in that, The system includes a quasi-zero stiffness support assembly and a suspension assembly, wherein: the quasi-zero stiffness support assembly includes a base plate (1), a load-bearing plate (3), and a positive stiffness elastic adjustment module, a magnetic negative stiffness module (10), a guide mechanism (5), and a displacement sensing unit (4) respectively disposed between the two; the magnetic negative stiffness module (10) and the positive stiffness elastic adjustment module are located on both sides of the guide mechanism (5), and both can extend and retract in the vertical direction to change the distance between the base plate (1) and the load-bearing plate (3); the stiffness of the positive stiffness elastic adjustment module is greater than the absolute value of the stiffness of the magnetic negative stiffness module (10), so that the quasi-zero stiffness support assembly... It exhibits positive stiffness characteristics; the suspension assembly includes a motor (9) and a suspension unit. The motor (9) is mounted on the load-bearing plate (3), and its output end is connected to the suspension unit. The end of the suspension unit is used to suspend the simulated object (13). The displacement sensing unit (4) can detect the relative displacement between the base plate (1) and the load-bearing plate (3) and transmit it to the external control unit. The external control unit can adjust the speed or torque of the motor (9) based on the relative displacement so that the relative displacement between the base plate (1) and the load-bearing plate (3) approaches 0, thereby keeping the support force of the quasi-zero stiffness support assembly on the suspension assembly constant.

2. The suspended microgravity simulation device as described in claim 1, characterized in that, The positive stiffness elastic adjustment module includes a positive stiffness spring (2) and a spring preload mechanism (11). The spring preload mechanism (11) is connected to the base plate (1). One end of the positive stiffness spring (2) is connected to the load-bearing plate (3), and the other end is connected to the spring preload mechanism (11).

3. The suspended microgravity simulation device as described in claim 2, characterized in that, The positive stiffness spring (2) and the magnetic negative stiffness module (10) are connected in parallel and arranged in parallel with each other.

4. The suspended microgravity simulation device as described in claim 1, characterized in that, The magnetic negative stiffness module (10) includes a stator (101) and a mover (102) coaxially mounted. The stator (101) is fixed on the load-bearing plate (3), and the mover (102) is fixed on the base plate (1).

5. The suspended microgravity simulation device as described in claim 1, characterized in that, The suspension assembly also includes a winch mechanism (6) and a drum (8). The winch mechanism (6) is connected to the output shaft of the motor (9). The drum (8) is installed on the output end of the winch mechanism (6), and the suspension unit is wound around the drum (8). When the motor (9) rotates, it can drive the winch mechanism (6) to rotate, thereby driving the drum (8) to take up and release the suspension unit.

6. The suspended microgravity simulation device as described in claim 5, characterized in that, The suspension unit is a steel wire rope (12), and a rope guide (7) is coaxially mounted on the outside of the drum (8) for guiding the steel wire rope (12).

7. The suspended microgravity simulation device as described in claim 6, characterized in that, The surface of the roller (8) is provided with a spiral guide groove, and the wire rope (12) is wound in the spiral guide groove.

8. The suspended microgravity simulation device as described in claim 1, characterized in that, The simulated object (13) is located below the base plate (1).

9. The suspended microgravity simulation device as described in any one of claims 1-8, characterized in that, The suspension unit is connected to the simulated object (13) via an elastic element (14); and / or, the elastic element (14) is a metal spring with a stiffness of 0.51 N / mm to 1 N / mm and a mass of no more than 10 g.

10. A method for simulating a micro-low gravity environment using a suspended micro-low gravity simulation device as described in any one of claims 1-9, characterized in that, include: S1 fixes the suspended micro-low gravity simulation device to the external frame in the surface gravity environment, and suspends the simulated object at the end of the suspension unit (13). S2 unlocks the guide mechanism (5) to release its vertical degree of freedom, so that the quasi-zero stiffness support assembly can only move vertically; S3 adjusts the positive stiffness elastic adjustment module to raise the load plate (3) so that the positive stiffness elastic adjustment module provides the full support force, thereby enabling the simulated object (13) to reach static equilibrium under the gravitational field. S4 continues to adjust the positive stiffness elastic adjustment module to make the load-bearing plate (3) continue to rise until the magnetic negative stiffness module (10) in static equilibrium works near the design zero point; S5 applies an external force vertically to the simulated object (13) to generate instantaneous acceleration. The tension of the suspension unit changes abruptly under the action of instantaneous acceleration, causing the horizontal height of the load-bearing plate (3) and the motor (9) to change. The displacement sensing unit (4) collects the relative displacement of the load-bearing plate (3) relative to the base plate (2) and transmits it to the external control unit. The external control unit can adjust the speed or torque of the motor (9) based on the relative displacement so that the relative displacement between the base plate (1) and the load-bearing plate (3) approaches 0, thereby keeping the support force of the quasi-zero stiffness support assembly on the suspension assembly constant.

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