A multi-attachment point active control gravity unloading device

Abstract

This invention discloses a multi-attachment point active control gravity unloading device, comprising: a structural support frame; three suspension units arranged in a triangle at the top fixed end, mounted on a three-axis displacement tracking slide. The three-axis displacement tracking slide is mounted on the structural support frame and includes three linear motion modules arranged along the X, Y, and Z axes. The three suspension units share two X-axis linear displacement mechanisms of the three-axis displacement tracking slide; each suspension unit independently possesses linear displacement mechanisms along the Y and Z axes of the three-axis displacement tracking slide; the three independent Y axes of the three-axis displacement tracking slide are parallel to each other, and the three independent Z axes are non-collinearly arranged on their respective independent Y axes. This invention achieves high-precision gravity unloading of a target during three-dimensional spatial motion and realizes a simulated environment with a microgravity level better than 10⁻²g. The system supports both forward and lateral mounting methods and has a wide range of three-dimensional motion tracking capabilities.

Description

Technical Field

[0001] This invention belongs to the field of aerospace technology, specifically relating to a multi-attachment point active control gravity unloading device. Background Technology

[0002] With the continuous development of aerospace technology, the role of space robots in orbit is becoming increasingly prominent. To ensure their reliable operation in space, thorough ground testing is necessary to simulate their kinematic and dynamic processes.

[0003] Currently, common gravity unloading methods include passive suspension, air-floating platform, drop tower, and traditional active suspension. While passive suspension is simple in structure and low in cost, the unloading force direction is fixed and its magnitude is difficult to adjust, making it only suitable for static tests with low precision. Air-floating platform methods are often used to simulate two-dimensional microgravity on a horizontal plane, but they cannot simulate vertical motion and suffer from aerodynamic interference and insufficient load-bearing capacity, making them unsuitable for multi-degree-of-freedom spatial motion simulations. Drop tower methods are mostly used for principle verification and are not suitable for system engineering testing. Traditional active suspension methods suffer from drawbacks such as control lag, circuit interference, and insufficient system precision.

[0004] In summary, existing technologies cannot simultaneously meet the combined requirements of high-precision microgravity level, large range of motion in space, multi-degree-of-freedom control response capability, and strong anti-interference capability for ground testing of space robots. Summary of the Invention

[0005] This invention addresses the problems existing in the prior art by proposing a multi-attachment point active control gravity unloading device. The purpose is to solve the problem that the existing technology cannot simultaneously meet the complex requirements of high-precision microgravity level, large spatial motion range, multi-degree-of-freedom control response capability, and strong anti-interference in ground testing of space robots.

[0006] To solve its technical problems, the present invention proposes the following technical solutions: A multi-point active control gravity unloading device, characterized in that it comprises: a structural support frame (1); three suspension units arranged in a triangular pattern at the top fixed end (6), the three suspension units being arranged on a three-axis displacement tracking slide (2, 3, 4), the three-axis displacement tracking slide being installed on the structural support frame (1), including three linear motion modules arranged along the X-axis, Y-axis and Z-axis directions; the three suspension units sharing two X-axis linear displacement mechanisms of the three-axis displacement tracking slide (2, 3, 4); each suspension unit independently possessing linear displacement mechanisms along the Y-axis and Z-axis of the three-axis displacement tracking slide (2, 3, 4), and being installed on the shared X-axis linear displacement mechanism via connectors; the three independent Y-axis of the three-axis displacement tracking slide (2, 3, 4) being parallel to each other, and the three independent Z-axis being non-collinearly arranged on their respective independent Y-axis; the top fixed end (6) of the three suspension units being connected to the three non-collinear Z-axis via their respective connecting plates (5). The upper part of the shaft and the bottom end are provided with a mounting interface (12) for connecting the target to be measured; the three suspension units are triaxial microgravity simulation suspension assemblies (6, 7, 8, 9, 10, 11); a tension sensor (7) is set on the microgravity simulation suspension assembly (6, 7, 8, 9, 10, 11) to measure the tension of the suspension unit; a tilt sensor (8) is set on the microgravity simulation suspension assembly (6, 7, 8, 9, 11). On 10, 11), used to measure the deflection angle of the suspension unit with respect to the vertical direction; an automatic control unit is electrically connected to the tension sensor (7), tilt sensor (8) of all the suspension units and the drive motor of the three-axis displacement tracking slide; wherein, the automatic control unit is configured to: independently control the movement of the corresponding three-axis displacement tracking slide according to the feedback signals of the tension sensor (7) and tilt sensor (8) of each suspension unit, so that each suspension unit remains in a vertical state and realizes multi-point dynamic gravity unloading of the target under test; Furthermore, in the three-axis displacement tracking slide, the linear motion module arranged along the X-axis is a gear and rack linear guide (2), and the linear motion modules arranged along the Y-axis and Z-axis are ball screw guide modules (3, 4); the entire system provides hardware support for the target to move within a space of 2.6m × 1.3m × 1.3m.

[0007] Furthermore, the tilt sensor (8) is a wireless tilt sensor, which transmits measurement data to the automatic control unit via wireless communication.

[0008] Furthermore, the mounting interface (12) includes a replaceable forward mounting interface and a side mounting interface.

[0009] Furthermore, the microgravity simulation suspension assembly also includes a cross-shaped universal hinge (11) connected above the mounting interface (12).

[0010] Furthermore, each suspension unit of the triaxial microgravity simulation suspension assembly (6, 7, 8, 9, 10, 11) includes: The top fixed end (6) is connected to the corresponding non-collinear Y-axis on the three-axis displacement tracking slide (2, 3, 4); A tension sensor (7) is used to measure the tension of a suspended target; Inclination sensor (8) is used to measure the angle of deviation of the suspension line from the vertical direction; Spring (9) is used to provide a certain degree of elasticity; A connecting rod (10) is used to connect the spring (9) to the mounting interface subsystem (12); A cross-shaped connector (11) is used to connect the connecting rod (10) to the mounting interface unit (12).

[0011] Advantages and effects of the present invention

[0012] 1. Achieving ultra-high precision microgravity simulation and overcoming the problem of insufficient accuracy: Addressing the low accuracy issues in microgravity simulation using existing technologies such as passive suspension, air-bearing platforms, and traditional active suspension, this invention utilizes an actively controlled anti-gravity unit. This unit integrates a tension sensor (7) and an tilt sensor (8) for real-time feedback. An automatic control unit independently drives the corresponding three-axis displacement tracking slide, ensuring that each suspension unit remains vertical. Precise unloading force is transmitted via a spring-straight rod mechanism (9, 10). Ultimately, a microgravity level better than 10⁻²g is achieved, meeting the high-precision testing requirements of space robots and other applications.

[0013] 2. Providing an ultra-large range of motion space, breaking through traditional size limitations: To solve the bottlenecks of limited motion range, such as the inability of air-bearing platforms to simulate vertical motion and the unsuitability of the drop tower method for engineering testing, this invention adopts a three-axis displacement tracking slide (X-axis gear rack 2, Y / Z-axis ball screws 3, 4) to construct a vast motion space of 2.6m × 1.3m × 1.3m, significantly expanding the movable range of the test object.

[0014] 3. Supports multi-degree-of-freedom coordination and rapid dynamic response, adapting to complex motion simulation: In view of the shortcomings of existing technologies in multi-degree-of-freedom coordinated control and complex motion simulation, this invention uses three suspension units arranged in a top triangle to work together, combined with feedback signals from multiple sets of sensors (7, 8), and the automatic control unit calculates and drives the three-axis displacement tracking slide (2, 3, 4) in real time, to achieve accurate dynamic tracking and rapid response to multi-degree-of-freedom motions such as target translation and attitude.

[0015] 4. Possesses strong anti-interference capability and high stability, overcoming control lag and signal interference: In order to eliminate the defects of control lag and line interference in the existing active suspension method, this invention constructs an anti-interference system combining hardware and software: a high-precision tension sensor (7) and a wireless tilt sensor (8) are used to reduce signal transmission interference; the slide motor is driven by an advanced control algorithm to ensure that the suspension point accurately follows the target centroid, thereby effectively suppressing external disturbances and ensuring the accuracy, repeatability and high stability of the test.

[0016] 5. Possessing high versatility and flexible configuration, improving the adaptability of test conditions: In order to improve the limitations of existing technologies in terms of adaptability to test conditions, the present invention provides two quick-change interfaces, namely forward and lateral, in the mounting interface unit (12), and integrates a ball joint structure, so that it can adapt to the test requirements of the target in different planes such as vertical plane and horizontal plane, and easily cope with diverse test tasks while ensuring the freedom of movement. Attached Figure Description

[0017] Figure 1 This is a block diagram of the ground-based active control gravity unloading device for simulating a space robot according to the present invention; Figure 2 Schematic diagram of the gantry section for the design of the active control gravity unloading device; Figure 3 A schematic diagram of the straight rod section for the design of an active gravity unloading device.

[0018] In the diagram: 1: Structural support frame; 2: X-axis gear rack linear guide; 3: Y-axis ball screw guide module; 4: Z-axis ball screw guide module; 5: Connecting plate; 6: Top fixed end; 7: Tension sensor; 8: Tilt sensor; 9: Spring; 10: Connecting rod; 11: Cross shaft connector; 12: Mounting interface. Detailed Implementation

[0019] Innovation of this invention

[0020] 1. Breakthrough in Precision: Achieving Ultra-High Precision Microgravity Simulation. Employing active closed-loop control combined with real-time feedback from high-precision tension sensors and wireless tilt sensors, a control algorithm drives a three-axis displacement mechanism to dynamically track the target, transmitting precise unloading force via a spring-rod mechanism. This overcomes the problems of low accuracy in passive suspension, the inability of air-bearing platforms to simulate vertical microgravity, the excessively short drop tower method time, and the control lag and significant interference of traditional active suspension methods. It achieves microgravity levels better than 10⁻² g, providing conditions for ground verification of high-precision space operations.

[0021] 2. Spatial Expansion: Provides an ultra-large range of motion space. Utilizing modular three-axis displacement tracking subunits (X-axis rack and pinion, Y / Z-axis ball screws) to form a gantry system, it overcomes the limitations of passive suspension and traditional active suspension's limited range of motion, as well as the difficulty of large-scale, continuous engineering testing using air-bearing platforms and drop tower methods. It provides a spacious three-axis motion space of 2.6m × 1.3m × 1.3m, supporting large-scale, long-term trajectory motion testing of the target object.

[0022] 3. Dynamic Performance: Achieving Multi-DOF Collaboration and Rapid Response. Through the coordinated operation of three suspension units arranged in a top triangle, integrating multiple sensors, and unified calculation by a central controller, nine servo motors drive the synchronous and precise tracking of the three-axis gantry. This overcomes the shortcomings of existing technologies (such as single-point suspension and passive systems) in simulating complex multi-DOF motion (three-axis translation and attitude changes) and rapid dynamic response. It can accurately and quickly track the spatial pose changes of the target's center of mass, realistically simulating the on-orbit motion of a space robot.

[0023] 4. Stable and Reliable: Possesses strong anti-interference capabilities and high stability. A hardware-software integrated anti-interference system is constructed: High-precision sensors and wireless transmission are used to reduce signal interference on the hardware side; advanced control algorithms are applied for real-time calculation and compensation on the software side. This effectively solves the problems of large unloading force fluctuations and poor test repeatability caused by control lag, signal noise, and line interference in traditional active suspension systems. External disturbances are significantly suppressed, ensuring high stability, high repeatability, and data accuracy during the testing process.

[0024] 5. Flexible Adaptability: Highly versatile and configurable. The mounting interface unit offers both forward and lateral quick-change interfaces and integrates a ball joint structure with adjustable spring preload. This improves upon the poor adaptability of existing technologies to test target configurations and testing conditions (such as vertical and horizontal movement). It can flexibly and quickly adapt to targets of different sizes, configurations, and testing requirements, ensuring their freedom of movement and expanding the device's testing application scenarios.

[0025] In summary, the core innovation of this invention lies in integrating the above five advantages to form a ground microgravity simulation system solution that is "high-precision, wide-range, fast-response, stable and anti-disturbance, and widely adaptable". It is especially suitable for simulating the high dynamic and multi-degree-of-freedom motion of equipment such as space robots in orbit, and has significant engineering application value.

[0026] Core design principle of this invention

[0027] 1. The organic combination of geometric stability and force-controlled compliance: The triangular structure provides static, inherent geometric stability, which is the foundation of the system's stiffness and load-bearing capacity. The three-axis slide provides dynamic, active displacement tracking capability, which is key to the system's compliance and precise unloading. The combination of the two achieves the effect of "stability without rigidity, and movement without chaos," ensuring the stability of the support while allowing the target to move freely and realistically.

[0028] 2. Kinematic Decoupling Design: Shared X-axis: Efficiently achieves overall horizontal translation of the measured target, with simple control and savings in cost and space. Independent Y-axis: Enables precise adjustment of the target's attitude (yaw) in the horizontal plane. Independent and non-collinear Z-axis: This is the essence of the design. It simultaneously performs two key functions: Gravity unloading: By independently adjusting the height, the tension of each suspension line is precisely controlled, and the combined force counteracts gravity. Pitch / roll attitude control: By forming a support surface through three non-collinear points, the pitch and roll attitude of the target can be directly controlled by adjusting the height difference of the three points. This design achieves functional decoupling and mechanism reuse of translation and attitude motion, gravity unloading and attitude control, greatly improving the system's control efficiency and flexibility.

[0029] 3. Multi-level closed-loop control ensures accuracy: Force closed loop (Z-axis): Using a tension sensor as feedback, the core objective is force balance, ensuring that gravity is accurately counteracted and simulating a microgravity environment. Geometric closed loop (X / Y-axis): Using an tilt sensor as feedback, the core objective is line perpendicularity, ensuring that the suspension force always passes through the target center of mass and does not introduce disturbing torque. These two closed loops are interlocked, together forming a highly robust active gravity compensation system that can effectively suppress external disturbances and internal system errors.

[0030] Based on the above principles, this invention designs a multi-attachment point active control gravity unloading device, such as... Figure 1-3As shown, its features include: a structural support frame 1; three suspension units arranged in a triangular pattern at their top fixed ends 6, which are mounted on three-axis displacement tracking slides 2, 3, and 4. The three-axis displacement tracking slides are mounted on the structural support frame 1 and include three linear motion modules arranged along the X, Y, and Z axes. The three suspension units share two X-axis linear displacement mechanisms of the three-axis displacement tracking slides 2, 3, and 4. Each suspension unit independently possesses linear displacement mechanisms along the Y and Z axes of the three-axis displacement tracking slides 2, 3, and 4, and is mounted to the shared X-axis linear displacement mechanism via connectors. The three independent Y axes of the three-axis displacement tracking slides 2, 3, and 4 are parallel to each other, and the three independent Z axes are non-collinearly arranged on their respective independent Y axes. The top fixed ends 6 of the three suspension units are respectively connected to the three non-collinear Z axes via their respective connecting plates 5. The upper part of the shaft and the bottom end are provided with a mounting interface 12 for connecting the target to be measured; the three suspension units are three-axis microgravity simulation suspension components 6, 7, 8, 9, 10, 11; a tension sensor 7 is set on the microgravity simulation suspension components 6, 7, 8, 9, 10, 11 for measuring the tension of the suspension unit; a tilt sensor 8 is set on the microgravity simulation suspension components 6, 7, 8, 9, 10, 11 for measuring the angle of deflection of the suspension unit with respect to the vertical direction; an automatic control unit is electrically connected to the tension sensor 7, tilt sensor 8 of all the suspension units and the drive motor of the three-axis displacement tracking slide; wherein, the automatic control unit is configured to: independently control the movement of the corresponding three-axis displacement tracking slide according to the feedback signals of the tension sensor 7 and tilt sensor 8 of each suspension unit, so that each suspension unit remains in a vertical state and realizes multi-point dynamic gravity unloading of the target to be measured; Supplementary Note 1: The target being tested is Figure 2 It is not shown in the diagram, but the target under test should be located at the lower end of the mounting interface 12.

[0031] like Figure 2 As shown, in the three-axis displacement tracking slide, the linear motion module arranged along the X-axis is a gear and rack linear guide 2, and the linear motion modules arranged along the Y-axis and Z-axis are ball screw guide modules 3 and 4; the entire system provides hardware support for the target to move within a space of 2.6m × 1.3m × 1.3m.

[0032] like Figure 2 As shown, the tilt sensor 8 is a wireless tilt sensor, which transmits measurement data to the automatic control unit via wireless communication.

[0033] like Figure 2 As shown, the mounting interface 12 includes a replaceable forward mounting interface and a side mounting interface.

[0034] Supplementary Note 2 : 1) The forward and lateral mounting interfaces have a wide range of three-dimensional motion tracking capabilities: X≥2.6m, Y≥1.3m, Z≥1.3m.

[0035] 2) The three suspension units arranged in a triangle at the top fixed end 6, combined with three sets of tension sensors 7 and three sets of wireless tilt sensors 8, monitor the suspension force and deflection angle in real time, and track the robot's movement by controlling the three-axis gantry system to achieve a simulated environment with a microgravity level better than 10⁻²g.

[0036] 3) The automatic control subunit includes a motor, an NI-CRIO lower-level machine, an NI multi-function data acquisition card, and a PC.

[0037] like Figure 2 As shown, the microgravity simulation suspension assembly also includes a cross-axis universal hinge 11 connected above the mounting interface 12.

[0038] like Figure 2 As shown, each suspension unit of the triaxial microgravity simulation suspension assembly 6, 7, 8, 9, 10, 11 includes: like Figure 2 As shown, the top fixed end 6 is connected to the corresponding non-collinear Y-axis on the three-axis displacement tracking slides 2, 3, and 4; Tension sensor 7 is used to measure the tension of the suspended target; Inclination sensor 8 is used to measure the angle of deviation of the suspension line from the vertical direction; Spring 9 is used to provide a certain degree of elasticity; The connecting rod 10 is used to connect the spring 9 to the mounting interface subsystem 12; The cross shaft connector 11 is used to connect the connecting rod 10 and the mounting interface unit 12.

[0039] It should be emphasized that the above specific embodiments are merely explanations of the present invention and are not intended to limit the present invention. After reading this specification, those skilled in the art can make modifications to the above embodiments without contributing any inventive step, but as long as they are within the scope of the claims of the present invention, they are protected by patent law.

Claims

1. A multi-attachment point active control gravity unloading device, characterized in that, include: Structural support frame (1); Three suspension units arranged in a triangle at the top fixed end (6), the three suspension units are arranged on a three-axis displacement tracking slide (2, 3, 4), the three-axis displacement tracking slide is installed on the structural support frame (1), including three linear motion modules arranged along the X-axis, Y-axis and Z-axis directions; Three suspension units share two X-axis linear displacement mechanisms of the three-axis displacement tracking slide (2, 3, 4); each suspension unit independently possesses linear displacement mechanisms in the Y and Z axes of the three-axis displacement tracking slide (2, 3, 4), and is mounted on the shared X-axis linear displacement mechanism via connectors; the three independent Y axes of the three-axis displacement tracking slide (2, 3, 4) are parallel to each other, and the three independent Z axes are non-collinearly arranged on their respective independent Y axes; the top fixed end (6) of the three suspension units is connected to the upper part of the three non-collinear Z axes via their respective connecting plates (5), and the bottom end is provided with a mounting interface (12) for connecting the target (13) to be measured; the three suspension units are three-axis microgravity simulation suspension assemblies (6, 7, 8, 9, 10, 11); a tension sensor (7) is installed in the microgravity simulation suspension assembly (6, 7, 8, 9, 11). On 10, 11), a tension sensor (8) is used to measure the tension of the suspension unit; an angle sensor (8) is set on the microgravity simulation suspension assembly (6, 7, 8, 9, 10, 11) to measure the angle of the suspension unit with respect to the vertical direction; an automatic control unit is electrically connected to the tension sensor (7), angle sensor (8) of all the suspension units and the drive motor of the three-axis displacement tracking slide; wherein, the automatic control unit is configured to: independently control the movement of the corresponding three-axis displacement tracking slide according to the feedback signals of the tension sensor (7) and angle sensor (8) of each suspension unit, so that each suspension unit remains in a vertical state and realizes multi-point dynamic gravity unloading of the target under test.

2. The multi-attachment point active control gravity unloading device according to claim 1, characterized in that, In the three-axis displacement tracking slide, the linear motion module arranged along the X-axis is a gear and rack linear guide (2), and the linear motion modules arranged along the Y-axis and Z-axis are ball screw guide modules (3, 4); the whole system provides hardware support for the target to move in a space of 2.6m × 1.3m × 1.3m.

3. A multi-attachment point active control gravity unloading device according to claim 1 or 2, characterized in that, The tilt sensor (8) is a wireless tilt sensor, which transmits measurement data to the automatic control unit via wireless communication.

4. The multi-attachment point active control gravity unloading device according to claim 1, characterized in that, The mounting interface (12) includes a replaceable forward mounting interface and a side mounting interface.

5. The multi-attachment point active control gravity unloading device according to claim 1, characterized in that, The microgravity simulation suspension assembly also includes a cross-axis universal hinge (11) connected above the mounting interface (12).

6. The multi-attachment point active control gravity unloading device according to claim 1, characterized in that, Each suspension unit of the triaxial microgravity simulation suspension assembly (6, 7, 8, 9, 10, 11) includes: The top fixed end (6) is connected to the corresponding non-collinear Y-axis on the three-axis displacement tracking slide (2, 3, 4); A tension sensor (7) is used to measure the tension of a suspended target; Inclination sensor (8) is used to measure the angle of deviation of the suspension line from the vertical direction; Spring (9) is used to provide a certain degree of elasticity; A connecting rod (10) is used to connect the spring (9) to the mounting interface; A cross-shaped connector (11) is used to connect the connecting rod (10) to the mounting interface.

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