High-precision gravity unloading device capable of three-dimensional movement

Abstract

The application discloses a high-precision gravity unloading device capable of realizing three-dimensional movement, and belongs to the field of gravity unloading. The device comprises an unloading truss assembly, first and second longitudinal guide rail assemblies with different installation heights, and two independent sets of movement units. Each set of movement units comprises a longitudinal trolley assembly slidably connected to the longitudinal guide rail assembly, a transverse guide rail assembly crossing between the longitudinal guide rail assemblies, a transverse trolley assembly slidably mounted on the transverse guide rail assembly, a fixed pulley assembly fixedly connected to the transverse trolley assembly, and a hanging rope connecting a measured rotating mechanism and a counterweight across the fixed pulley assembly. By arranging the two sets of independent movement units, the high-low staggered longitudinal guide rail layout is used to avoid structural interference when multiple unloading points move in the longitudinal direction. By optimizing the layout of the fixed pulley and the counterweight, three-dimensional high-precision dynamic follow-up unloading of a complex double-shaft rotating mechanism in a large rotation angle range is realized, and a reliable microgravity environment simulation for ground testing of spaceflight equipment is provided.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of gravity unloading, and particularly relates to a high-precision gravity unloading device capable of realizing three-dimensional motion, which is especially suitable for dynamic follow-up unloading of a complex double-axle rotating mechanism under a ground-simulated microgravity environment. BACKGROUND

[0002] When testing spaceflight equipment on the ground, in order to accurately simulate the microgravity environment in space, the spaceflight equipment needs to be subjected to gravity unloading. Existing unloading methods mainly include active unloading and passive unloading. The active unloading usually adopts motor active tracking control, which has high precision but is high in cost and complex in system. In the passive unloading, the air floating platform method is only suitable for motion unloading in the horizontal plane, and has limited scope of application; the mechanical hanging method is low in cost and can be used for gravity unloading in two-dimensional or three-dimensional motion, for example, it has been applied in simple unfolding mechanisms such as solar wings. However, the existing mechanical hanging device usually only has one set of longitudinal guide rails, and when multiple transverse guide rails move on the longitudinal guide rails, structural interference is easily caused, and the requirement for the opposite staggered motion of multiple unloading points in the longitudinal direction cannot be met. Especially for a complex double-axle rotating mechanism, the rotating shaft direction is neither perpendicular nor parallel to the gravity direction, and the motion components of the unloading points in the longitudinal direction are staggered, so the existing device cannot realize effective and high-precision three-dimensional follow-up unloading. SUMMARY

[0003] The present application aims to solve the problems of structural interference, low unloading precision and limited stroke range of the existing gravity unloading schemes, and provides a gravity unloading device which is simple in structure, high in unloading precision and capable of realizing three-dimensional motion. The device is based on the mechanical hanging principle and includes transverse / longitudinal trolley, transverse / longitudinal guide rod, fixed pulley and hanging rope, etc. By optimizing the installation height difference of the longitudinal guide rail assembly, the size of the counterweight and the size of the fixed pulley and other structural parameters, the interference problem of multiple unloading points when the transverse displacement is coincided is effectively avoided, the transverse unloading stroke is expanded, and the frictional resistance of the hanging rope is reduced, so that large-angle and high-precision dynamic follow-up unloading of a complex double-axle rotating mechanism is realized.

[0004] To achieve the above-mentioned purpose, the technical solution provided by the present application is as follows:

[0005] A high-precision gravity unloading device capable of realizing three-dimensional motion is provided, which includes an unloading truss assembly, a first longitudinal guide rail assembly and a second longitudinal guide rail assembly which are installed in parallel on the unloading truss assembly and have different installation heights, and two independent sets of motion units.

[0006] Each set of motion units includes:

[0007] a longitudinal trolley assembly which is slidingly connected to the first longitudinal guide rail assembly or the second longitudinal guide rail assembly;

[0008] - a transverse rail assembly, two ends of the transverse rail assembly being bridged between the first longitudinal rail assembly or the second longitudinal rail assembly through a longitudinal trolley assembly and being capable of sliding along the extension direction of the corresponding longitudinal rail assembly;

[0009] - a transverse trolley assembly, the transverse trolley assembly being slidingly installed on the transverse rail assembly to slide along the extension direction of the transverse rail assembly;

[0010] - a fixed pulley assembly, the fixed pulley assembly being fixedly connected to the transverse trolley assembly to move together with the transverse trolley assembly;

[0011] - a hoisting rope, one end of the hoisting rope being used for connecting one unloading point of the measured rotating mechanism, and the other end of the hoisting rope being wound around the fixed pulley assembly;

[0012] - a counterweight, the counterweight being connected to the end of the hoisting rope wound around the fixed pulley assembly;

[0013] The hoisting ropes of the two sets of motion units are respectively connected to two unloading points of the measured rotating mechanism to realize dynamic follow-up gravity unloading of the measured rotating mechanism in three-dimensional space motion.

[0014] Further, the installation height difference between the first longitudinal rail assembly and the second longitudinal rail assembly is greater than the height dimension of the longitudinal trolley assembly in the vertical direction.

[0015] Further, each set of longitudinal rail assemblies comprises two parallel guide rods and limiting assemblies arranged at the two ends of the guide rods.

[0016] Further, the longitudinal trolley assembly and the transverse trolley assembly each comprise a C-shaped bracket and a plurality of pairs of bearings installed on the C-shaped bracket, the bearings being in rolling fit with the corresponding guide rods to realize sliding of the longitudinal trolley assembly and the transverse trolley assembly.

[0017] Further, the limiting assembly comprises a limiting screw and a limiting nut, the limiting screw passing through a lateral through hole at the end of the guide rod and being locked and fixed by the limiting nut.

[0018] Further, the size of the counterweight in the guide direction of the transverse rail assembly is less than the diameter of the pulley in the fixed pulley assembly.

[0019] Further, the gravity unloading device further comprises a mounting seat for mounting the measured rotating mechanism, the mounting seat being fixed to the unloading truss assembly.

[0020] Further, the mounting seat comprises a base plate and a support frame connected to the base plate; the base plate is used for connecting with the unloading truss assembly; and the support frame is used for providing a mounting interface with the measured rotating mechanism.

[0021] Further, the unloading truss assembly is a rigid frame structure composed of a plurality of bars and joints.

[0022] Further, the hanging rope adopts aramid rope.

[0023] The advantages of the present application are:

[0024] 1. The gravity unloading device provided by the present application effectively solves the structural interference problem of the existing mechanical hanging device when moving longitudinally towards or staggered at multiple unloading points, and significantly expands the horizontal movement stroke, by adopting two groups of first longitudinal guide rail assemblies and second longitudinal guide rail assemblies with height difference, and configuring two completely independent motion units.

[0025] 2. The device can simulate high-precision, long-stroke mechanism movement in a space microgravity environment in a ground environment, making the mechanism movement function verification and load performance test results more realistic and reliable, and providing reliable ground test basis for ground testing of spaceflight equipment such as scanning tracking antennas and space mechanical arms. BRIEF DESCRIPTION OF DRAWINGS

[0026] The above and / or other features and advantages of the present application will become more apparent by describing in following reference to the accompanying drawings, which are not drawn to scale, and some features are enlarged or reduced to show details of certain components, in which:

[0027] Figure 1 is a planar structure schematic diagram of the gravity unloading device of the present application;

[0028] Figure 2 is a three-dimensional structure schematic diagram of the gravity unloading device of the present application;

[0029] Figure 3 is a three-dimensional structure schematic diagram of the first longitudinal guide rail assembly in the present application;

[0030] Figure 4 is a three-dimensional structure schematic diagram of the second longitudinal guide rail assembly in the present application;

[0031] Figure 5 is a three-dimensional structure schematic diagram of the longitudinal trolley assembly and the horizontal trolley assembly in the present application;

[0032] Figure 6 is a three-dimensional structure schematic diagram of the horizontal guide rail assembly in the present application;

[0033] Figure 7is a schematic diagram of the vertical structure of the fixed pulley assembly in the application;

[0034] Figure 8 is a schematic diagram of the vertical structure of the mounting seat in the application.

[0035] In the figure: 1 - unloading truss assembly; 2 - first longitudinal guide rail assembly, 21 - first guide rod, 22 - first connecting screw, 23 - first connecting nut, 24 - first limiting screw; 3 - second longitudinal guide rail assembly, 31 - second guide rod, 32 - second connecting screw, 33 - second connecting nut, 34 - second limiting screw; 4 - longitudinal trolley assembly, 41 - C-shaped support, 42 - bearing, 43 - pin, 44 - pin hole; 5 - transverse guide rail assembly; 6 - transverse trolley assembly; 7 - fixed pulley assembly, 71 - support, 72 - pulley, 73 - pulley shaft; 8 - hoisting rope; 9 - counterweight; 10 - mounting seat, 101 - base plate, 102 - support frame; 11 - measured rotating mechanism. DETAILED DESCRIPTION

[0036] The application will be described in detail below with reference to the accompanying drawings and exemplary embodiments of the application. It should be pointed out that the following detailed description of the application is for illustrative purposes only and is not limiting on the application.

[0037] It should be pointed out that in the context of the application, the orientations or positional relationships indicated by the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "inner", "outer", "clockwise" and "counterclockwise" are based on the orientations or positional relationships shown in the drawings and are only for the convenience of describing the application and simplifying the description, and therefore cannot be understood as limiting the application in that the indicated devices or elements must have a particular orientation, be constructed and operated in a particular orientation.

[0038] In addition, terms such as "first" and "second" are only for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features. Therefore, features defined with "first" and "second" can explicitly or implicitly include one or more of the features.

[0039] Reference Figure 1 and Figure 2 As an example of an embodiment of the application, the high-precision gravity unloading device capable of three-dimensional motion includes an unloading truss assembly 1, a first longitudinal guide rail assembly 2, a second longitudinal guide rail assembly 3, and two independent sets of motion units, each set of motion units including a longitudinal trolley assembly 4, a transverse guide rail assembly 5, a transverse trolley assembly 6, a fixed pulley assembly 7, a hoisting rope 8 and a counterweight 9.

[0040] The unloading truss assembly 1 is a space frame type rigid structure assembled by a plurality of bars through connecting joints, which provides a stable mounting base for the whole device.

[0041] In combination Figure 3 and Figure 4 The first longitudinal guide rail assembly 2 and the second longitudinal guide rail assembly 3 are installed in parallel on the upper part of the unloading truss assembly 1 through connecting screws and connecting nuts of different lengths to realize two groups of longitudinal guide rail assemblies with different installation heights (Y direction in the figure). Specifically, the first longitudinal guide rail assembly 2 is fixed to the unloading truss assembly 1 through the first connecting screw 22 and the first connecting nut 23; the second longitudinal guide rail assembly 3 is fixed to the unloading truss assembly 1 through the second connecting screw 32 and the first connecting nut 33.

[0042] In some embodiments of the present application, both groups of longitudinal guide rail assemblies are mainly composed of two parallel longitudinal guide rods and limiting assemblies installed at both ends thereof. Specifically, the first longitudinal guide rail assembly 2 includes two parallel first guide rods 21, and the second longitudinal guide rail assembly 3 includes two parallel second guide rods 31. The limiting assembly of the first longitudinal guide rail assembly 2 includes a first limiting screw 24 and a first limiting nut (not labeled in the figure), and the limiting assembly of the second longitudinal guide rail assembly 3 includes a second limiting screw 34 and a second limiting nut (not labeled in the figure). The first limiting screw 24 and the second limiting screw 34 pass through the lateral through holes on the corresponding guide rods and are locked with the limiting nuts to prevent the longitudinal trolley assembly 4 to be described below from being detached from the end of the guide rod.

[0043] In the shown embodiment, the installation height of the first longitudinal guide rail assembly 2 is higher than that of the second longitudinal guide rail assembly 3, and the installation height difference therebetween is precisely designed to be greater than the profile height of the longitudinal trolley assembly 4 in the vertical direction. This height difference is the key to ensure that the longitudinal trolley assembly 4 is structurally interfered when the transverse trolley assembly 6 moves transversely (X direction in the figure), thereby providing the necessary conditions for realizing the large stroke movement in the transverse direction (X direction in the figure) (the high longitudinal guide rail side is +X direction, and the low longitudinal guide rail side is -X direction), thus meeting the stroke requirement of the unloading point.

[0044] In combination Figure 5 and Figure 6Two ends of the transverse rail assembly 5 are bridged between two guide rods in the first longitudinal rail assembly 2 or two guide rods in the second longitudinal rail assembly 3, and a set of longitudinal trolley assemblies 4 are installed on each end by screws, which have the function of limiting the movement of components on the transverse rail assembly 5. In the preferred embodiment, the longitudinal trolley assembly 4 includes a C-shaped bracket 41 and a plurality of pairs of high-precision bearings 42 mounted on the C-shaped bracket 41, which can be installed at both ends of the C-shaped bracket 41 through pins 43, and the two bearings at opposite ends form a pair of bearings. The pins 43 are installed by passing through the pin holes 44 machined at the ends of the C-shaped bracket 41. Two sets of longitudinal trolley assemblies 4 are respectively sleeved on the guide rods of the first longitudinal rail assembly 2 and the second longitudinal rail assembly 3, and through the rolling of the bearings on the guide rods, the smooth movement of the entire transverse rail assembly 5 along the extension direction of the longitudinal rail assembly, i.e. the longitudinal direction (Z direction in the figure) can be achieved.

[0045] On the guide rods of each transverse rail assembly 5, a set of slidable transverse trolley assemblies 6 are installed. The structure of the transverse trolley assembly 6 is the same as that of the longitudinal trolley assembly 4, also composed of a C-shaped bracket and a pair of bearings, to achieve precise sliding in the extension direction of the transverse rail assembly 5, i.e. the transverse direction (X direction).

[0046] In combination Figure 7 The fixed pulley assembly 7 is fixedly installed to the transverse trolley assembly 6, especially its lower end, to move together with the transverse trolley assembly 6 in the transverse and longitudinal directions. The fixed pulley assembly 7 mainly includes a support 71, a pulley 72 and a pulley shaft 73. The support 71 is a block-shaped metal member, and the upper part thereof is provided with a mounting hole connected with the transverse trolley assembly 6, and the fixed connection between the two can be achieved by bolts. The lower part of the support 71 is provided with a U-shaped opening, and the two sides of the opening are provided with coaxial shaft holes for passing through the pulley shaft 73. The pulley 72 is supported on the middle shaft diameter part of the pulley shaft 73, and a part is located in the U-shaped opening of the support 71, so that the pulley 72 can rotate flexibly relative to the pulley shaft 73. The outer periphery of the pulley 72 is provided with an annular rope groove for accommodating and guiding the hoisting rope 8.

[0047] The hoisting rope 8 preferably uses aramid rope with high elastic modulus, one end of which is connected to the unloading point of the measured rotating mechanism 11, and the other end is wound around the pulley 72 of the fixed pulley assembly 7 and connected with the counterweight 9. The size of the counterweight 9 in the X direction is designed to be smaller than the diameter of the pulley 72, so as to avoid structural interference with the hoisting rope 8 during movement.

[0048] In combination Figure 8In an alternative embodiment of the present application, to achieve a firm installation of the measured mechanism, the gravity unloading device can comprise a mounting seat 10 fixed to the unloading truss assembly 1. Preferably, the mounting seat 10 can comprise a base plate 101 for connection with the truss, and a support frame 102 connected with the base plate 101, for example in the form of a triangular support, the bottom of which provides a mounting interface with the measured rotating mechanism 11.

[0049] The two sets of movement units of the device are respectively connected to two unloading points P1, P2 of the measured rotating mechanism 11. During the movement of the rotating mechanism, its center of mass is a virtual point in space and cannot be directly unloaded, and it is equivalent to the unloading of two real points, i.e. the center point of the intersection of P1 and P2 is the center of mass. The movement trajectories of the two unloading points are spatial curves, and there are displacement components in X, Y and Z directions. In the unloading device, the counterweights move in accordance with the displacement of the unloading points, and dynamic follow-up unloading during the movement of the mechanism can be achieved.

[0050] The working process of the unloading device is as follows: when the measured rotating mechanism 11 starts to move and drives the two unloading points P1, P2 to move in space, each unloading point dynamically follows the corresponding counterweight 9 through its sling 8. Specifically, the movement of the unloading point is first guided by the sling 8 to drive the pulley in the fixed pulley assembly 7 to rotate, thereby achieving the displacement of the counterweight 9 in the Y direction; secondly, the fixed pulley assembly 7 and the horizontal trolley assembly 6 in which it is located slide in the X direction along the horizontal guide rail assembly 5, thereby achieving the X direction movement of the counterweight 9; finally, the horizontal guide rail assembly 5 slides in the Z direction on the high and low longitudinal guide rails through the longitudinal trolley assemblies 4 at both ends, thereby achieving the Z direction movement of the counterweight 9. Since the two sets of movement units operate on longitudinal guide rails at different heights, structural interference caused by the opposite or staggered movement of the unloading points in complex trajectories, especially in large angle movement, is fundamentally avoided, thereby achieving dynamic follow-up gravity unloading of a complex double-axis rotating mechanism in the entire three-dimensional space with large angle and high precision.

[0051] In addition, the displacement stroke expansion of the unloading device is as follows: the Y direction can achieve displacement stroke expansion by lengthening the size of the longitudinal guide rod; the Z direction can achieve displacement stroke expansion by increasing the installation height of the longitudinal guide rail assembly 2 and the mechanism mounting bracket 10; the -X direction can achieve displacement stroke expansion in the -X direction by lengthening the size of the horizontal guide rod; and the +X direction can further achieve displacement stroke expansion in the +X direction by reducing the trolley assembly.

[0052] Finally, it should be noted that features mentioned and / or shown in the above description of exemplary embodiments of the application can be combined with one or more other embodiments, either in the same or in different embodiments, than those in which the features are described. The technical solutions obtained by combining the features in this way should also be regarded as included in the scope of protection of the application.

Claims

1. A high-precision gravity unloading device capable of three-dimensional movement, characterized in that: The device comprises an unloading truss assembly (1), first and second longitudinal guide rail assemblies (2, 3) installed in parallel on the unloading truss assembly (1) and at different heights, and two independent sets of motion units; Each set of motion units comprises: a longitudinal trolley assembly (4) slidingly connected to the first or second longitudinal guide rail assembly (2, 3); a transverse guide rail assembly (5) having two ends straddling the first or second longitudinal guide rail assembly (2, 3) through the longitudinal trolley assembly (4) and being capable of sliding along the extension direction of the corresponding longitudinal guide rail assembly; a transverse trolley assembly (6) slidingly installed on the transverse guide rail assembly (5) to slide along the extension direction of the transverse guide rail assembly (5); a fixed pulley assembly (7) fixed to the transverse trolley assembly (6) to move together with the transverse trolley assembly (6); a sling (8) having one end connected to an unloading point of a measured rotating mechanism (11) and the other end passing through the fixed pulley assembly (7); a counterweight (9) connected to the end of the sling (8) passing through the fixed pulley assembly (7); The slings (8) of the two sets of motion units are respectively connected to two unloading points of the measured rotating mechanism (11) to achieve dynamic follow-up gravity unloading of the measured rotating mechanism (11) in three-dimensional space motion.

2. The high-precision gravity unloading device capable of three-dimensional movement according to claim 1, characterized in that: The height difference between the first longitudinal guide rail assembly (2) and the second longitudinal guide rail assembly (3) is greater than the vertical height dimension of the longitudinal trolley assembly (4).

3. The high-precision gravity unloading device capable of three-dimensional movement according to claim 1 or 2, characterized in that: Each longitudinal guide rail assembly comprises two parallel guide rods and limiting assemblies arranged at the two ends of the guide rods.

4. The high-precision gravity unloading device capable of three-dimensional movement according to claim 3, characterized in that: The longitudinal trolley assembly (4) and the transverse trolley assembly (6) each comprise a C-shaped bracket and a plurality of pairs of bearings installed on the C-shaped bracket, the bearings being in rolling contact with the corresponding guide rods to achieve the sliding of the longitudinal trolley assembly (4) and the transverse trolley assembly (6).

5. The high-precision gravity unloading device capable of three-dimensional movement according to claim 3, characterized in that: The limiting assembly comprises a limiting screw and a limiting nut, the limiting screw passing through a lateral through hole at the end of the guide rod and being locked and fixed by the limiting nut.

6. The high-precision gravity unloading device capable of three-dimensional movement according to claim 1 or 2, characterized in that: The size of the counterweight (9) in the guide direction of the transverse guide rail assembly (5) is smaller than the diameter of the pulley in the fixed pulley assembly (7).

7. The high-precision gravity unloading device capable of three-dimensional movement according to claim 1 or 2, characterized in that: An installation seat (10) for installing the measured rotating mechanism (11) is further included, the installation seat (10) being fixed to the unloading truss assembly (1).

8. The high-precision gravity unloading device capable of three-dimensional movement according to claim 7, characterized in that: The installation seat (10) comprises a base plate (101) and a support frame (102) connected to the base plate (101); the base plate (101) is used to connect with the unloading truss assembly (1); and the support frame (102) is used to provide an installation interface with the measured rotating mechanism (11).

9. The high-precision gravity unloading device capable of three-dimensional movement according to claim 1 or 2, characterized in that: The unloading truss assembly (1) is a rigid frame structure composed of a plurality of rod members and joints.

10. The high-precision gravity unloading device capable of three-dimensional movement according to claim 1 or 2, characterized in that: The hoisting rope (8) is made of aramid rope. The hoisting rope (8) is made of aramid rope.

Images