Gas magnetic overhanging type micro-low gravity test air floating workbench for inhibiting residual magnetism and eddy current interference

Abstract

The invention discloses an air-magnetic overhanging type micro-low gravity test air-floating workbench capable of inhibiting residual magnetism and eddy current interference. The air-magnetic overhanging type micro-low gravity test air-floating workbench comprises a rigid bearing framework and a functional composite material layer. The rigid bearing framework is made of non-magnetic high-specific-stiffness aluminum alloy, and mechanical supporting and magnetic field isolation are achieved. And the functional composite material layer is compounded by uniformly dispersing and consolidating corrosion-resistant nickel-based soft magnetic particles in a non-magnetic matrix, and is used as a gas-magnetic coupling working interface. The adopted nickel-based soft magnetic particles have high saturation flux density, low coercive force, high resistivity and good chemical stability, it is ensured that the functional composite material layer formed by the nickel-based soft magnetic particles has lasting and reliable working surface performance, and residual magnetism interference force and eddy current damping force are fundamentally eliminated on the premise that needed vertical adsorption force is maintained. According to the design, the unexpected horizontal disturbing force generated by the air floatation working table is reduced to one thousandth of the rated vertical bearing force of the gas magnetic bearing, and the precision of dynamic simulation in a micro-low gravity ground experiment is remarkably improved.

Description

Technical Field

[0001] This invention pertains to aerospace ground simulation equipment, specifically relating to an air-floating worktable for a gas-magnetic hybrid bearing system used in micro / low gravity experiments. Background Technology

[0002] High-fidelity simulation of microgravity environments on the ground is essential for the development of satellite technology, space robots, and on-orbit precision instruments. Among these methods, suspension and air-floatation are two commonly used microgravity testing techniques: suspension is suitable for ground deployment tests of lightweight, large-sized spacecraft structures; air-floatation provides a high-precision microgravity testing environment. The air-magnetic hybrid suspension microgravity testing system combines the advantages of both methods. In the air-magnetic hybrid suspension unit, the air bearing provides frictionless support, while the electromagnetic unit provides the vertical suspension force. This testing system is one of the ideal solutions for achieving high-precision motion simulation experiments in microgravity environments.

[0003] However, in air-magnetic hybrid suspension micro-low gravity test systems, the air-floating platform, as one of the core components, generally uses an integrated magnetically conductive metal (such as cast iron or electrical pure iron) as the structural matrix. This traditional configuration introduces two types of intrinsic magnetic interferences at the physical level that cannot be actively compensated for:

[0004] First, there is the nonlinear resistance caused by remanent magnetization: after the magnetic metal is locally magnetized by the bearing's magnetic unit, the internal magnetic domains cannot fully recover, resulting in a spatially unevenly distributed remanent magnetic field on the surface. When the bearing moves, it is relatively misaligned with the remanent magnetic region on the platform, and the remanent magnetic field generates horizontal resistance on the bearing, hindering its movement. This external force disrupts the near-zero external force ideal environment required for microgravity experiments.

[0005] Second, the dynamic damping force caused by eddy current interference induced by the sweeping magnetic field: When the aeromagnetic suspension unit moves relative to the platform, the magnetic field of the aeromagnetic suspension unit sweeps at high speed relative to the low-resistivity metal platform. According to Faraday's law of electromagnetic induction, macroscopic eddy currents are generated inside the platform, which in turn generate an electromagnetic damping force opposite to the direction of motion. This velocity-dependent viscous effect is not a real space physics environment, causing the simulation system to lose its "intrinsic low-damping" dynamic characteristics.

[0006] Existing technologies mostly focus on algorithm-level compensation or end-effector vibration isolation, but none of them can eradicate these two types of intrinsic interference forces from their physical source, namely the material properties of the worktable and the magnetic circuit configuration. Therefore, developing a new type of worktable that can achieve magnetic circuit discretization constraints, block eddy current paths at the structural level, and suppress residual magnetism accumulation has become an urgent need for constructing a high-fidelity ground simulation environment. Summary of the Invention

[0007] In response to the above-mentioned prior art, the present invention provides a composite structure worktable that can significantly suppress the interference force and eddy current damping force caused by residual magnetism under high-speed and light-load conditions. The present invention aims to overcome the systematic obstacles of traditional magnetically conductive metal air-bearing worktables in simulating micro-low gravity environments on the ground, including: (1) interference force caused by residual magnetism: the "false external force" background caused by the high residual magnetic induction intensity after excitation of traditional metal; (2) damping force caused by eddy current: the dynamic eddy current damping force excited by the sweeping magnetic field destroys the "zero resistance" characteristic of the simulated environment; (3) environmental failure problem: after the high-precision grinding required for air-bearing, traditional iron-based magnetic materials are prone to corrosion, which in turn damages the flatness of the air film and contaminates the experimental environment.

[0008] To address the aforementioned technical problems, this invention proposes an air-magnetic inverted micro-low gravity test air-floating workbench that suppresses residual magnetism and eddy current interference. The air-floating workbench includes a rigid support structure made of non-magnetic material and a functional composite material layer fixed to the support structure. The functional composite material layer is composed of nickel-based soft magnetic particles uniformly dispersed and solidified in a non-magnetic matrix.

[0009] Furthermore, in the air flotation worktable of the present invention:

[0010] In the functional composite material layer, the material of the non-magnetic matrix is ​​epoxy resin or unsaturated polyester resin, the weight percentage of the nickel-based soft magnetic particles is 30% to 80%, and the percentage of the non-magnetic matrix is ​​20% to 70%.

[0011] The functional composite material layer is prepared by mixing the nickel-based soft magnetic particles with a non-magnetic matrix material according to a weight percentage, and then molding the mixture to obtain the final product.

[0012] The functional composite material layer is integrated with the rigid support structure through mechanical connection or bonding process.

[0013] The non-magnetic material used to fabricate the rigid load-bearing structure is an aluminum alloy.

[0014] Compared with existing technologies, this invention, through fundamental innovation in materials and structure, aims to provide a basic platform for microgravity simulation experiments with ultra-low force noise and high force control accuracy. This invention overturns the traditional design paradigm of "single continuous magnetic conductor" and proposes a composite structural scheme of "magnetic-mechanical functional decoupling and magnetic circuit discretization." The air-bearing stage of this invention achieves synergistic optimization of multi-physics performance, specifically bringing the following beneficial effects:

[0015] (1) Root cause suppression of magnetic interference: Discrete nickel-based particles constrain the magnetic domain motion to the micrometer scale, reducing the overall remanent background to near zero, which greatly reduces the interference to microgravity simulation experiments.

[0016] (2) Eliminating eddy current interference resistance: This structure effectively blocks the formation of macroscopic eddies, resulting in extremely low eddy current damping force generated by the worktable during movement, thereby greatly improving the accuracy of dynamic simulation.

[0017] (3) High environmental stability and long life precision: Thanks to the corrosion resistance of nickel-based particles, even when the particles are exposed due to precision machining, the working surface can still maintain good roughness for a long time, avoiding the material degradation problems such as rust and powdering that are prone to occur on the working surface of traditional magnetic platforms, and ensuring the long-term stability of the micro morphology and performance of the precision working surface.

[0018] (4) Reliable structure and high maintainability: The load-bearing structure is made of high-strength metal, ensuring the overall structural strength and hoisting safety. The multi-functional composite layer, as a functional module, can be repaired or replaced individually after long-term wear and tear, significantly reducing the total life cycle cost. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of a high-fidelity space unfolding mechanism ground dynamics simulation system according to an embodiment of the present invention;

[0020] Figure 2 for Figure 1 The diagram shows a longitudinal cross-sectional view of the air flotation workbench.

[0021] Figure 3 for Figure 2 A partial cross-sectional view of the air flotation workbench shown.

[0022] Figure 4 for Figure 1 The top view of the rigid load-bearing structure 100 shown.

[0023] In the diagram: 100 - Rigid load-bearing structure, 110 - Reinforcing rib, 120 - Lifting interface, 200 - Functional composite material layer, 210 - Nickel-based soft magnetic particles, 220 - Non-magnetic matrix, 300 - Mechanical interface system, 310 - T-head bolt, 320 - Hexagonal nut, 400 - Hybrid air-magnetic suspension unit, 500 - Folding mechanism, 600 - Truss. Detailed Implementation

[0024] The present invention proposes a design concept for an air-magnetic inverted micro-low gravity test air-floating workbench that suppresses remanent magnetization and eddy current interference. This air-floating workbench is designed to significantly suppress interference forces caused by remanent magnetization and eddy current damping forces under high-speed, light-load conditions. The air-floating workbench includes a functional composite material layer fixed to a rigid support structure. The rigid support structure is made of a high-stiffness aluminum alloy of non-magnetic material to achieve mechanical support and magnetic field isolation. The functional composite material layer is composed of corrosion-resistant nickel-based soft magnetic particles uniformly dispersed and solidified in a non-magnetic matrix, thus serving as the working interface for air-magnetic coupling. The nickel-based soft magnetic particles used in this working interface provide the required soft magnetic properties (high saturation magnetic flux density, low coercivity, high resistivity) while also possessing good chemical stability. This ensures that the functional composite material layer has durable and reliable working surface performance, fundamentally eliminating interference forces caused by remanent magnetization and eddy current damping forces induced by the sweeping magnetic field while maintaining the required vertical adsorption force. The design of this working interface reduces the unexpected horizontal disturbance force generated by the air-floating worktable to one-thousandth of the rated vertical load capacity of the air-magnetic bearing, significantly improving the accuracy of dynamic simulation in micro-low gravity ground experiments.

[0025] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, but the following embodiments are by no means intended to limit the present invention.

[0026] This invention proposes a pneumatically suspended micro-low gravity experimental air-floating worktable for suppressing residual magnetism and eddy current interference, such as... Figure 2 and Figure 3 As shown, the air-floating worktable includes a rigid support structure 100 made of a non-magnetic material and a functional composite material layer 200 fixed to the support structure 100. To meet the stringent requirements of lightweight structure, high rigidity, and reliable connections under high-speed, light-load conditions, the support structure 100 in the air-floating worktable of this invention is made of high-stiffness aluminum alloy. Aluminum alloy is a non-ferromagnetic material, which can meet the requirements of the support structure for non-magnetic properties, thereby effectively avoiding hysteresis and eddy current interference introduced by the structure itself. This rigid support structure 100 serves as a non-magnetic, high-stiffness support body, thereby achieving mechanical support and magnetic field isolation for the air-floating worktable. Figure 3As shown, the functional composite material layer 200 is composed of corrosion-resistant nickel-based soft magnetic particles as the functional phase, which are uniformly dispersed and solidified in a non-magnetic matrix 220. The nickel-based soft magnetic particles (such as nickel-iron alloy or permalloy particles) possess intrinsic high magnetic permeability and excellent chemical stability. The non-magnetic matrix 220 is made of epoxy resin or unsaturated polyester resin. In the functional composite material layer 200, the weight percentage of the nickel-based soft magnetic particles 210 is 30% to 80%, and the percentage of the non-magnetic matrix 220 is 20% to 70%. The functional composite material layer 200 is prepared by mixing the nickel-based soft magnetic particles 210 and the non-magnetic matrix material according to the weight percentages, and then molding the mixture to obtain the final product. When the functional composite material layer 200 is mechanically connected or bonded to the rigid support structure 100, and this air-floating worktable is used in a gas-magnetic hybrid suspension micro-low gravity test system, the functional composite material layer 200 interacts directly with the gas-magnetic hybrid bearing. Its working surface is precision-ground, with a flatness ≤5μm / m. Because the working surface of the multifunctional composite material layer 200 needs to achieve the air-floating support accuracy through grinding, some microscopic cross-sections of the nickel-based soft magnetic particles are exposed on the surface. Due to their self-passivation properties, the nickel-based particles can resist the erosion of air and air source humidity without the need for coating protection, avoiding microscopic morphological damage and increased surface roughness caused by particle oxidation, expansion, or corrosion, thus maintaining the stability of the working surface performance over a long period.

[0027] Research materials:

[0028] In this invention, the physical dimensions and material composition design of the functional composite material layer 200, which serves as a functional composite module, follow the principle of multi-physics coupling optimization. Its core design criteria are derived from the following theoretical model:

[0029] (1) Effective Medium Theory of Equivalent Permeability. Volume fraction of discrete soft magnetic particles within the functional surface layer. This determines the overall macroscopic magnetic permeability of the device. According to the Maxwell-Garnett approximation model, the equivalent relative permeability of the functional layer... With particle permeability and matrix permeability The following mapping relationship is satisfied:

[0030]

[0031] In the formula, The volume fraction of soft magnetic particles (dimensionless). is the relative permeability (dimensionless) of the soft magnetic particles. This represents the relative permeability (dimensionless) of the non-magnetic matrix. Design criteria require precise adjustment... The value of, makes It is in the linear response range that can guide the magnetic flux to close without causing excessively rapid magnetic saturation.

[0032] (2) Microscopic blocking model of eddy current loss. To suppress eddy current heating in the background technology, the morphological design of the functional composite material layer 200 in this invention needs to meet the electromagnetic energy dissipation constraints at the microscale. In a time-varying magnetic field Under the action, the particle diameter and layer thickness Power loss per unit area determined by the joint Follow these physical principles:

[0033]

[0034] In the formula, The power loss per unit area of ​​eddy current (W / m²) is the power loss per unit area of ​​eddy current. The thickness (m) of the functional composite material layer; The equivalent resistivity of the composite material is (Ω·m). denoted as Wb, representing the magnetic flux (Wb) passing through the cross section. Time (s); The coordinates (m) are along the thickness direction. The insulating coating on the particle surface significantly increases the equivalent resistivity. This criterion establishes the need to limit particle feature size. With the total thickness of the surface layer The product term provides the theoretical basis for actively controlling macroscopic Joule heat.

[0035] Example: A high-fidelity ground dynamics simulation system for a space folding mechanism. Figure 1 The simulation system is shown. Figures 2 to 4 The structure of the air flotation worktable is shown.

[0036] like Figure 1 As shown, the air-floating worktable proposed in this invention is used to provide a working interface for the planar motion air-magnetic hybrid suspension unit 400. Below the air-magnetic hybrid suspension unit 400 is a folding mechanism 500, and the entire simulation system is supported by a truss 600. This air-floating worktable is a rectangular plate-shaped device (e.g., Figure 4 As shown), its design goal is to reduce the background of horizontal residual magnetic interference force and damping force caused by eddy current introduced by the air-bearing worktable to an extremely low level (the target value is less than one-thousandth of the rated load capacity of the bearing) under the conditions of high-speed operation (>0.5 m / s) and light load (rated load <500N).

[0037] like Figures 1 to 4 As shown, the air-floating workbench proposed in this invention mainly consists of two functionally and physically distinct component modules (rigid load-bearing structure 100 and functional composite material layer 200). The rigid load-bearing structure 100 and the multifunctional composite material layer 200 are directly and rigidly combined through a mechanical interface system 300 to form a complete integrated workbench, achieving strict functional separation and physical integration. The magnetic function is completely confined within the thin layer of the multifunctional composite material layer 200, while all mechanical load-bearing tasks are undertaken by the rigid load-bearing structure 100. The two do not rely on the performance of adhesives or flexible buffer layers, but achieve a stable and reliable connection only through mechanical interlocking, resulting in a simple form and high reliability. Among them, the rigid load-bearing structure 100, as the main support structure of the air-floating workbench, is formed by machining a single piece of non-magnetic aluminum alloy. The overall shape is rectangular plate, and its form is designed as a box-shaped frame with internal reinforcing ribs 110. Its function is to provide the overall rigidity and strength required by the device, and it contains all the hoisting interfaces 120 and the mechanical interfaces (pre-embedded threaded connectors) for system integration. The key feature of this module is that its material itself is non-ferromagnetic, fundamentally eliminating the possibility of generating eddy currents or remanence as part of a magnetic circuit. The functional composite layer 200 serves as the working interface of the aeromagnetic suspension unit. This functional composite layer 200 is a freestanding, pre-formed plate-like component. It is a composite material containing uniformly distributed nickel-based soft magnetic particles, provided as a complete functional unit. Its function is to replace the traditional integrated metal platform, providing the aeromagnetic hybrid suspension unit with a high-resistivity, low-eddy-current, and nearly remanence-free high-performance working surface. As a mechanical interface system 300, during the casting process of the functional composite layer 200, such as... Figure 2 and Figure 3 As shown, a stainless steel T-head bolt 310 is pre-embedded every 230mm. After the functional composite material layer is cured, it is rigidly locked to the aluminum alloy rigid load-bearing frame 100 through the mechanical interface system 300, namely the array of T-head bolts 310 (and hexagonal nuts 320), ensuring that there is no relative slippage between the rigid load-bearing frame 100 and the functional composite material layer 200.

[0038] This invention's air-floating worktable fundamentally alters the closed path of magnetic field lines and the path of mechanical force transmission by integrating a non-magnetic rigid load-bearing structure 100 with a functional composite material layer 200 composed of an epoxy resin (or unsaturated polyester resin) matrix and corrosion-resistant nickel-based soft magnetic particles. The magnetic circuit of the air-floating platform is effectively constrained and discretized within the insulating particle network of the functional modules, significantly increasing the overall equivalent resistivity of the device and suppressing eddy current effects and remanence to extremely low levels. The anticipated effect is that the unexpected level of interference introduced by this device can be reduced by more than two orders of magnitude compared to traditional cast iron platforms, reaching the level of one-thousandth of the rated bearing capacity.

[0039] Although the invention has been described above in conjunction with the accompanying drawings, it is not limited to the specific embodiments described above. These embodiments are merely illustrative and not restrictive. This embodiment clearly demonstrates how the fundamental problems identified in the background art can be systematically solved through the proposed separate, modular composite device form, rather than a specific process. Those skilled in the art, inspired by this invention, can make many improvements and variations without departing from its spirit. For example, the core technical means of combining a non-magnetic rigid load-bearing structure with a functional composite material layer composed of nickel-based soft magnetic particles are all within the protection scope of this invention.

Claims

1. A pneumatic magnetic inverted micro-low gravity experimental air-floating workbench for suppressing residual magnetism and eddy current interference, characterized in that, The air-bearing workbench includes a rigid support structure (100) made of non-magnetic material and a functional composite material layer (200) fixed to the support structure (100). The functional composite material layer (200) is composed of nickel-based soft magnetic particles (210) uniformly dispersed and solidified in a non-magnetic matrix (220).

2. The air flotation workbench according to claim 1, characterized in that, In the functional composite material layer (200), the material of the non-magnetic matrix (220) is epoxy resin or unsaturated polyester resin, the weight percentage of the nickel-based soft magnetic particles (210) is 30% to 80%, and the percentage of the non-magnetic matrix (220) is 20% to 70%.

3. The air flotation workbench according to claim 2, characterized in that, The functional composite material layer (200) is prepared by mixing the nickel-based soft magnetic particles (210) with a non-magnetic matrix material according to a weight percentage, and then molding the mixture to obtain the final product.

4. The air flotation workbench according to claim 3, characterized in that, The functional composite material layer (200) is integrated with the rigid support structure (100) by mechanical connection or bonding process.

5. The air flotation workbench according to claim 1, characterized in that, The non-magnetic material used to make the rigid load-bearing structure (100) is an aluminum alloy.

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