A passive compliant docking assist device with six degrees of freedom

Abstract

The application provides a passive compliant docking auxiliary device with six degrees of freedom, which solves the problems of small application range, low measurability and low reliability of the passive compliant docking auxiliary device in the existing rocket propellant automatic filling system. The passive compliant docking auxiliary device comprises a static platform and a dynamic platform which are connected with each other, the static platform comprises a bottom plate and a top plate which are parallel to each other; the bottom plate and the top plate are connected through a plurality of guide rail assemblies which are symmetrically distributed on the static platform, and the guide rail assemblies are provided with compliant connecting assemblies in the axial direction; the compliant connecting assemblies comprise elastic components, sliding blocks which are slidingly connected with the guide rail assemblies, and supporting components which are used for providing supporting force to the sliding blocks, the elastic components and the supporting components are symmetrically arranged on the two sides of the sliding blocks and are in contact with the sliding blocks without being connected; the sliding blocks are movably connected with the dynamic platform through a motion branch chain; and the dynamic platform is arranged close to the top plate of the static platform. The application is widely applied in the field of aerospace module docking technology.

Description

Technical Field

[0001] This application relates to the field of aerospace module docking technology, and more specifically, to a passive compliant docking auxiliary device with six degrees of freedom. Background Technology

[0002] Cryogenic liquid propellants are flammable, volatile, and explosive. To reduce safety hazards during propellant loading, automated rocket propellant loading systems have become the primary method. Existing automated rocket propellant loading systems connect to the rocket body via a loading / unloading connector. During loading, the rocket body is affected by external conditions such as the launch site environment, fuel weight changes, and wind loads, resulting in unpredictable slight vibrations and random errors. These errors are difficult to compensate for precisely through automatic control, thus affecting the stability and adaptability of the loading / unloading connector's connection to the rocket body, leading to unsuccessful automatic docking.

[0003] Chinese patent CN109318210B discloses a 13-DOF (DoF) active-passive compliant attitude adjustment docking platform and its flexible docking method. The platform comprises four parts: a mobile platform, an active attitude adjustment platform, a passive compliant platform, and a load-bearing moving platform. The mobile platform is located on a guide rail assembly at the bottom. The active attitude adjustment platform is located on the mobile platform, with its upper platform frame two connected in series with the passive compliant platform. The upper platform frame three of the passive compliant platform is connected to the load-bearing moving platform. Both the active attitude adjustment platform and the passive compliant platform are six-DOF parallel mechanisms. The active attitude adjustment platform uses electric push rods to actively adjust the six-DOF position and attitude of the frame two. Each leg of the passive compliant platform is equipped with springs and sensors to achieve compliant movement and micro-motion detection during the docking process. The load-bearing moving platform can fix the load-bearing compartment.

[0004] The above-mentioned technical solution has the advantages of high detection accuracy and high docking efficiency. However, when the load of the docking mechanism changes, the double-spring compliant legs of the passive compliant platform cannot adjust the compliant position in time. Under the condition of excessive load or severe external disturbance, it is easy to exceed the adjustment range of the legs. The legs need to be replaced with springs to ensure that compliant position adjustment can be achieved. Therefore, the applicable scope is small, the measurability and reliability of the passive compliant platform are low, and the stability of the automatic docking of the venting connector and the rocket body is affected. Summary of the Invention

[0005] To address the aforementioned problems, the present invention provides a passive compliant docking auxiliary device with six degrees of freedom, characterized by high measurability, reliability, and wide applicability. This device compensates for the positional errors between the active and passive docking mechanisms, improving the stability of the relative position and orientation of the connectors during the movement of the active docking mechanism. The device comprises a static platform and a moving platform connected to each other. The static platform includes a bottom plate and a top plate that are parallel to each other. The bottom and top plates are connected by multiple guide rail assemblies symmetrically distributed on the static platform. Each guide rail assembly has a compliant connecting component along its axial direction. The compliant connecting component includes an elastic component, a slider slidably connected to the guide rail assembly, and a support component providing support for the slider. The elastic component and the support component are symmetrically arranged on both sides of the slider and are in contact with but not connected to the slider. The slider is movably connected to the moving platform via a kinematic chain. The moving platform is positioned near the top plate of the static platform.

[0006] Preferably, the support component includes a piston rod and a cylinder disposed on the surface of the stationary platform. The piston end of the piston rod is slidably connected to the inner cavity of the cylinder, and the other end of the piston rod is in contact with the slider but not connected.

[0007] Preferably, the slider is initially positioned in the middle of its sliding stroke, and the piston end on the piston rod is initially positioned at the maximum volume of the rodless chamber of the cylinder.

[0008] Preferably, the natural length of the elastic component is greater than the sliding stroke of the slider.

[0009] Preferably, the number of guide rail assemblies, compliant connection assemblies, and motion chains are all six.

[0010] Preferably, the two ends of the motion chain are connected to the moving platform and the slider through ball joints.

[0011] Preferably, the compliant connecting components are divided into three groups from top to bottom along the direction of gravity. The two compliant connecting components in the same group are symmetrically distributed with the direction of gravity and the direction of docking in the same plane. The supporting force provided by the supporting component in the upper group of compliant connecting components points away from the moving platform, and the supporting force provided by the supporting component in the lower two groups of compliant connecting components points towards the moving platform.

[0012] Preferably, a Cartesian coordinate system O-YZ is established with the plane containing the center of the static platform as the origin, the negative direction of gravity as the Z-axis, and the Y-axis horizontal. Six ball joints are symmetrically distributed along the Z-axis in the center of the static platform. The ball joints along the positive Y-axis are A1, A2, and A3 in sequence along the direction of gravity, and the deflection angles of A1, A2, and A3 from the positive Z-axis are qa1, qa2, and qa3, respectively. A Cartesian coordinate system O-YZ is established with the plane containing the moving platform as the origin. A rectangular coordinate system O1-Y1Z1 is established with the center of the moving platform as the origin and the negative direction of gravity as the Z1 axis. The Y1 axis is horizontal. There are six ball joints symmetrically distributed along the Z1 axis on the moving platform. The ball joints along the positive direction of the Y1 axis are B1, B2, and B3 in sequence along the direction of gravity. The deflection angles of B1, B2, and B3 from the positive direction of the Z1 axis are qb1, qb2, and qb3, respectively. qb1 < qa1, qb2 > qa2, and qb3 > qa3.

[0013] Preferably, the end of the elastic component away from the slider is connected to a guide rod, which is mounted on the surface of the stationary platform.

[0014] Preferably, the surface of the moving platform is connected to a venting connector, and the top plate surface of the stationary platform is connected to an actuator of the active docking mechanism, which cooperates with the passive docking mechanism for docking.

[0015] The beneficial effects of this invention are as follows: 1. The elastic component and the support component are symmetrically arranged on both sides of the slider and are in contact with the slider but not connected, which shortens the stroke of the elastic component and the support component; the support component stably provides support force to the slider, and the elastic component always applies force to the slider. The overall sliding stroke of the slider is short and the offset is small. When the docking guide pin of the active docking mechanism contacts the interface of the passive docking mechanism, passive compliance adjustment is performed according to the position of the contact point and the direction of the common normal of the contact point, so as to complete the position adjustment of the moving platform and its connected venting connector, making the active docking mechanism adapt to the interface of the passive docking mechanism and successfully complete the docking. 2. The six sets of compliant connection components are symmetrically distributed along the direction of gravity. The support force provided by the support component in the upper set of compliant connection components points away from the moving platform, and the support force provided by the support component in the lower two sets of compliant connection components points towards the moving platform. This allows the compliant connection components to stably balance the load and ensure the stability of the relative position of the moving platform and its connected venting connector when moving with acceleration in all directions within a certain range. 3. It can adjust the air pressure inside the cylinder and the prestress of the spring according to the load and external disturbances, with high compatibility, high measurability of passive compliant adjustment, convenient operation, and wide applicability. 4. The moving platform is positioned close to the top plate of the stationary platform, and the slider is initially located in the middle of its sliding stroke. This shortens the distance between the center of the moving platform and the center of the stationary platform, reduces the length of the passive compliant docking auxiliary device in the docking direction, reduces the overall length and dimensional changes of the active docking mechanism in the initial position, and lowers the load on the umbilical arm of the rocket launch tower. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a schematic diagram of the structure of the present invention;

[0018] Figure 2 This is a schematic diagram of the structure of the present invention from another angle:

[0019] Figure 3 This is a structural diagram of a compliant connection component;

[0020] Figure 4 This is a structural diagram of the supporting component in its initial position;

[0021] Figure 5 for Figure 4 A cross-sectional view of the central support component;

[0022] Figure 6 This is a schematic diagram of the structure of a kinematic branch;

[0023] Figure 7 This is a schematic diagram of the Cartesian coordinates of the present invention;

[0024] Figure 8 A schematic diagram showing the position of the ball joint on a static platform;

[0025] Figure 9 This is a schematic diagram showing the position of the ball joint on the moving platform.

[0026] Symbols in the diagram: 1. Static platform; 101. Base plate; 102. Top plate; 2. Moving platform; 3. Guide rail assembly; 4. Compliant connection assembly; 401. Slider; 402. Spring; 403. Cylinder; 404. Piston rod; 5. Motion chain; 6. Ball joint; 7. Guide rod. Detailed Implementation

[0027] To make the technical problems, technical solutions, and beneficial effects to be solved by 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 are not intended to limit the scope of this application.

[0028] It should be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0029] It should be noted that the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0030] The present application will now describe a passive compliant docking auxiliary device with six degrees of freedom provided in the embodiments of this application.

[0031] Please see Figure 1 and Figure 2 The diagram shows the structure of the invention from different angles. The passive compliant docking auxiliary device with six degrees of freedom includes a static platform 1 and a moving platform 2 connected to each other. The static platform 1 includes a bottom plate 101 and a top plate 102 that are parallel to each other. The bottom plate 101 and the top plate 102 of the static platform 1 are connected by a plurality of guide rail assemblies 3 symmetrically distributed on the static platform 1. The guide rail assemblies 3 are provided with compliant connecting assemblies 4 axially. The compliant connecting assemblies 4 include an elastic component, a slider 401 that is slidably connected to the guide rail assembly 3, and a support component for providing support force to the slider 401. The elastic component and the support component are symmetrically arranged on both sides of the slider 401 and are in contact with the slider 401 but not connected. The slider 401 is movably connected to the moving platform 2 through a motion chain 5. The moving platform 2 is located near the top plate 102 of the static platform 1.

[0032] The guide rail assembly 3 is fixedly connected to the top plate 102 and bottom plate 101 of the stationary platform 1 at both ends by connectors including but not limited to bolts. The distance between the top plate 102 and the bottom plate 101 and the length of the guide rail assembly 3 limit the maximum and minimum sliding stroke of the slider 401 to ensure that the accessible working space of the moving platform 2 meets the design requirements. The moving platform 2 is positioned close to the top plate 102 of the stationary platform 1 to shorten the distance from the center of the moving platform 2 to the center of the stationary platform 1 in the initial position, reduce the length of the passive compliant docking auxiliary device in the docking direction, reduce the overall length and dimensional changes of the active docking mechanism in the initial position, and reduce the load on the umbilical arm of the rocket launch tower.

[0033] Please see Figure 3This is a schematic diagram of the compliant connection assembly 4. The elastic and supporting components in the compliant connection assembly 4 provide flexible support and absorb energy for the slider 401. When the slider 401 slides towards the supporting component, the supporting component stably provides supporting force to the slider 401, giving the compliant connection assembly 4 a certain rigidity and maintaining the stability of the moving platform 2. Specifically, the supporting component includes a piston rod 404 and a cylinder 403 disposed on the surface of the stationary platform 1. The piston end of the piston rod 404 is slidably connected to the inner cavity of the cylinder 403, and the other end of the piston rod 404 is in contact with the slider 401 but not connected. As a supporting component, cylinder 403 has small dynamic changes in output force, is easy to maintain, and can stably support the load caused by gravity of the moving platform 2 and the active docking mechanism. During installation, gas is filled into the inner cavity of cylinder 403. When the load changes or external disturbances are severe, the air pressure in the inner cavity of cylinder 403 can be controlled to adapt to different situations. It has strong controllability and does not require the installation or disassembly of supporting components. Only the air pressure in the inner cavity of cylinder 403 and the prestress of the elastic component at the initial position need to be controlled. No control or adjustment is required in other stages. It is easy to operate and has a wide range of applications.

[0034] Please see Figure 4 and Figure 5 The diagram shows the structure and cross-sectional view of the supporting component in its initial position. Further, the slider 401 is initially positioned at the middle of its sliding stroke, and the piston end on the piston rod 404 is initially positioned at the maximum volume of the rodless chamber of the cylinder 403. When the slider 401 moves towards the cylinder 403, the cylinder 403 stably provides supporting force. The piston rod 404 of the cylinder 403 contacts the slider 401, but the two are not connected. This optimizes the volume of the cylinder 403, reduces the stroke of the piston rod 404, and ensures that supporting force is only provided when the slider 401 contacts and moves towards the cylinder 403. The overall stroke is small, and the movement range of the motion chain 5 is less restricted.

[0035] Furthermore, the natural length of the elastic component under no force is greater than the sliding stroke of the slider 401. The elastic component is always under pressure throughout the entire sliding stroke of the slider 401, so as to ensure that the slider 401 will receive the force of the elastic component when it slides to any position, thus playing a role in smooth adjustment.

[0036] Specifically, the elastic component can be a spring 402, a flexible hinge, a gas spring, or similar structure. In this embodiment, the elastic component is specifically a spring 402. The spring 402 has a simple structure, low cost, and is easy to maintain. The spring 402 contacts the slider 401, but the two are not connected, making installation simple and saving space, thus controlling the length of the entire device in the docking direction. During passive compliant docking, the spring 402 is always in a compressed state, applying a force to the slider 401.

[0037] Furthermore, the number of guide rail assembly 3, compliant connection assembly 4, and motion chain 5 are all six, in order to avoid the lack of degrees of freedom of the moving platform 2 and to ensure that the moving platform 2 can perform six degrees of freedom of pose adjustment.

[0038] Please see Figure 1 , Figure 2 and Figure 6 The two ends of the motion chain 5 are connected to the moving platform 2 and the slider 401 via ball joints 6. The ball joint 6 can be a spherical bearing, universal joint, or other structures. In this embodiment, the ball joint 6 is specifically a spherical bearing; specifically, the slider 401 and the moving platform 2 are provided with perforated columns, and pins are inserted into the holes of the columns. The spherical bearing is mounted on the pins, and the pins are fixed in radial position by elastic retaining rings. The spherical bearing is fixed in axial position by axial elastic retaining rings.

[0039] Please see Figure 7 The diagram shows a Cartesian coordinate system for this invention. The negative direction of the z-axis is the direction of gravity, the x-axis is the docking direction, and the y-axis is horizontal. The gravity of the active docking mechanism, equivalent to the center of the moving platform 2, can be decomposed into a force along the negative z-axis and a torque about the y-axis. Further, the compliant connecting components 4 are divided into three groups from top to bottom along the direction of gravity, with two compliant connecting components 4 in the same group symmetrically distributed with respect to the planes where the direction of gravity and the docking direction are located. To balance the load caused by the gravity of the active docking mechanism, the supporting force provided by the supporting components in the upper group of compliant connecting components 4 points away from the moving platform 2, while the supporting force provided by the supporting components in the lower two groups of compliant connecting components 4 points towards the moving platform 2; please refer to [link to relevant documentation]. Figure 1 and Figure 2 Specifically, the cylinder 403 in the upper set of compliant connection components 4 is installed on the outer surface of the top plate 102 of the stationary platform 1, and the corresponding piston rod 404 provides a supporting force to the slider 401 in a direction away from the moving platform 2. The cylinder 403 in the lower two sets of compliant connection components 4 is installed on the outer surface of the bottom plate 101 of the stationary platform 1, and the corresponding piston rod 404 provides a supporting force to the slider 401 in a direction close to the moving platform 2, so as to ensure that the six compliant connection components 4 can stably balance the load, so that the passive compliant docking auxiliary device can adjust the position of the moving platform 2 and its connected venting connector in the horizontal direction, and the direction of gravity of its load is parallel to the moving platform 2. The docking auxiliary device in the prior art usually adjusts the position of the connected load in the vertical direction, and the direction of gravity of its load is perpendicular to the moving platform.

[0040] Please see Figure 8 and Figure 9The diagrams show the positions of the ball joints 6 on the static platform 1 and the moving platform 2, respectively. A Cartesian coordinate system O-YZ is established with the plane containing the middle part of the static platform 1 as the origin, the negative direction of gravity as the Z-axis, and the Y-axis as the horizontal axis. There are six ball joints 6 symmetrically distributed along the Z-axis in the middle part of the static platform 1. The ball joints 6 in the positive direction of the Y-axis are A1, A2, and A3 in sequence along the direction of gravity, and the deflection angles of A1, A2, and A3 from the positive direction of the Z-axis are qa1, qa2, and qa3 in sequence. The ball joints 6 in the negative direction of the Y-axis are symmetrically distributed with A1, A2, and A3, and are A6, A5, and A4 in sequence along the direction of gravity. A Cartesian coordinate system O1-Y1Z1 is established on the plane containing the moving platform 2, with the center of the moving platform 2 as the origin, the negative direction of gravity as the Z1 axis, and the Y1 axis being horizontal. The moving platform 2 has six ball joints 6 symmetrically distributed along the Z1 axis. The ball joints 6 in the positive direction of the Y1 axis are B1, B2, and B3 along the direction of gravity, with deflection angles of qb1, qb2, and qb3 respectively from the positive direction of the Z1 axis. The ball joints 6 in the negative direction of the Y1 axis are symmetrically distributed with B1, B2, and B3, and are B6, B5, and B4 along the direction of gravity. qb1 < qa1, qb2 > qa2, and qb3 > qa3 to ensure that the force provided by each set of cylinders 403 and piston rods 404 in balancing gravity is thrust, thus ensuring the stability of the relative posture of the moving platform 2 and its connected venting connectors when moving with accelerations in all directions within a certain numerical range.

[0041] Please see Figure 1 , Figure 2 and Figure 7 One side of slider 401 contacts but is not connected to the piston rod 404 of cylinder 403, while the other side contacts but is not connected to spring 402. Piston rod 404 contacts slider 401, bearing the load caused by the gravity of the moving platform 2 and the active docking mechanism. When slider 401 moves towards cylinder 403, spring 402 always acts on slider 401, ensuring that both ends are stressed and maintaining stability. When the acceleration of the entire device is small, when slider 401 moves towards spring 402, under the action of gravity, slider 401 will move towards cylinder 403 again. The overall sliding stroke is short, and the offset is small, ensuring the stability of the relative position and attitude of the active docking mechanism connected to the moving platform 2. It can adjust the air pressure inside cylinder 403 and the prestress of spring 402 according to the load and external disturbances, exhibiting high compatibility, high measurability of passive compliant adjustment, convenient operation, and wide applicability.

[0042] Furthermore, a guide rod 7 is connected to the end of the elastic component away from the slider 401. The guide rod 7 is mounted on the surface of the stationary platform 1, opposite to the mounting direction of the cylinder 403, and is used to mount the spring 402.

[0043] Specifically, the surface of the moving platform 2 is connected to a venting connector via connectors including but not limited to bolts, and the surface of the top plate 102 of the stationary platform 1 is connected to the execution component of the active docking mechanism via connectors including but not limited to bolts. The active docking mechanism and the passive docking mechanism cooperate to dock, and the passive docking mechanism is the rocket body. When the execution component of the active docking mechanism connected to the stationary platform 1 moves with an acceleration in all directions within a certain range, the elastic component and the support component in the flexible connection component 4 cause the slider 401 to be subjected to force at both ends, preventing the slider 401 from driving the motion chain 5 to move along the guide rail assembly 3, thus ensuring the stability of the relative posture of the moving platform 2 and the venting connector connected thereto.

[0044] The working process of this invention is as follows: When the docking guide pin of the active docking mechanism contacts the interface of the passive docking mechanism, the moving platform 2 of the passive compliant docking auxiliary device generates a corresponding positional change according to the position of the contact point and the direction of the common normal of the contact point. The movement of the moving platform 2 is transferred to the movement of the slider 401 on the guide rail assembly 3 through the ball joint 6 and the motion chain 5. The elastic components and support components on both sides of the slider 401 passively and compliantly adjust the positional change of the moving platform 2 to complete the positional adjustment of the venting connector, so that the active docking mechanism adapts to the interface of the passive docking mechanism and completes the docking. When the execution component of the active docking mechanism moves with an acceleration in all directions within a certain range, the elastic components and support components cause the slider 401 to be subjected to force at both ends, preventing the slider 401 from being displaced along the guide rail assembly 3, so that the moving platform 2 and the venting connector connected thereto are relatively stable in position during operation.

[0045] In this invention, 1. The elastic component and the support component are symmetrically arranged on both sides of the slider 401 and are in contact with the slider 401 but not connected, shortening the stroke of the elastic component and the support component; the support component stably provides support force to the slider 401, and the elastic component always applies force to the slider 401. The overall sliding stroke of the slider 401 is short and the offset is small. When the docking guide pin of the active docking mechanism contacts the interface of the passive docking mechanism, passive compliance adjustment is performed according to the position of the contact point and the direction of the common normal of the contact point, completing the position adjustment of the moving platform and its connected venting connector, so that the active docking mechanism adapts to the interface of the passive docking mechanism and successfully completes the docking. 2. Six sets of compliant connection components 4 are symmetrically distributed along the direction of gravity. The support force provided by the support component in the upper set of compliant connection components 4 points away from the moving platform 2, and the support force provided by the support component in the lower two sets of compliant connection components 4 points towards the moving platform 2, so that the compliant connection components 4 can stably balance the load and ensure the stability of the relative position of the moving platform 2 and its connected venting connector when moving with acceleration in all directions within a certain range. 3. It can adjust the air pressure inside cylinder 403 and the prestress of spring 402 according to the load and external disturbances, with high compatibility, high measurability of passive compliant adjustment, convenient operation, and wide applicability. 4. The moving platform 2 is positioned close to the top plate of the stationary platform 1, and the slider 401 is initially located in the middle of its sliding stroke. This shortens the distance from the center of the moving platform 2 to the center of the stationary platform 1, reduces the length of the passive compliant docking auxiliary device in the docking direction, reduces the overall length and dimensional changes of the active docking mechanism in the initial position, and reduces the load on the umbilical arm of the rocket launch tower.

[0046] The specific embodiments described above do not cover the entire scope of protection of this application. Modifications or equivalent substitutions to the invention should all fall within the patent coverage requirements of this application. In this invention, the above-described embodiments are only used to illustrate the technical solutions of this application, and not to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application, and should all be included within the protection scope of this application.

Claims

1. A passive compliant docking auxiliary device with six degrees of freedom, comprising a static platform (1) and a moving platform (2) connected to each other, wherein the static platform (1) comprises a bottom plate (101) and a top plate (102) that are parallel to each other; characterized in that: The base plate (101) and the top plate (102) are connected by a plurality of guide rail assemblies (3) symmetrically distributed on the stationary platform (1). The guide rail assembly (3) is provided with a compliant connection assembly (4) in the axial direction. The compliant connection assembly (4) includes an elastic component, a slider (401) slidably connected to the guide rail assembly (3), and a support component for providing support force to the slider (401). The elastic component and the support component are symmetrically arranged on both sides of the slider (401) and are in contact with the slider (401) but not connected. The slider (401) is movably connected to the moving platform (2) through a motion chain (5). The moving platform (2) is located close to the top plate (102) of the stationary platform (1). The support component includes a piston rod (404) and a cylinder (403) disposed on the surface of the stationary platform (1). The piston end of the piston rod (404) is slidably connected to the inner cavity of the cylinder (403), and the other end of the piston rod (404) is in contact with the slider (401) but not connected. The slider (401) is initially located in the middle of the sliding stroke, and the piston end on the piston rod (404) is initially located at the maximum volume of the rodless chamber of the cylinder (403). The two ends of the motion chain (5) are connected to the moving platform (2) and the slider (401) through ball joints (6); The compliant connecting components (4) are divided into three groups from top to bottom along the direction of gravity. The two compliant connecting components (4) in the same group are symmetrically distributed with the direction of gravity and the docking direction in the same plane. The supporting force provided by the supporting component in the upper group of compliant connecting components (4) points away from the moving platform (2), and the supporting force provided by the supporting component in the lower two groups of compliant connecting components (4) points towards the moving platform (2). A Cartesian coordinate system O-YZ is established on the plane containing the middle part of the static platform (1). The center of the static platform (1) is the origin, the negative direction of gravity is the Z-axis, and the Y-axis is horizontal. The middle part of the static platform (1) is provided with six ball joints (6) symmetrically distributed along the Z-axis. The ball joints (6) in the positive direction of the Y-axis are A1, A2, and A3 in sequence along the direction of gravity. The deflection angles of A1, A2, and A3 with the positive direction of the Z-axis are qa1, qa2, and qa3 in sequence. A Cartesian coordinate system O-YZ is established on the plane containing the moving platform (2). The vertical plane rectangular coordinate system O1-Y1Z1 has the center of the moving platform (2) as the origin, the negative direction of gravity as the Z1 axis, and the Y1 axis as the horizontal axis. The moving platform (2) is provided with six ball joints (6) symmetrically distributed along the Z1 axis. The ball joints (6) in the positive direction of the Y1 axis are B1, B2, and B3 in sequence along the direction of gravity. The deflection angles of B1, B2, and B3 with the positive direction of the Z1 axis are qb1, qb2, and qb3 in sequence. qb1 < qa1, qb2 > qa2, and qb3 > qa3.

2. The passive compliant docking auxiliary device with six degrees of freedom as described in claim 1, characterized in that: The natural length of the elastic component is greater than the sliding stroke of the slider (401).

3. The passive compliant docking auxiliary device with six degrees of freedom as described in claim 1, characterized in that: The number of the guide rail assembly (3), the compliant connection assembly (4), and the motion branch (5) are all six.

4. The passive compliant docking auxiliary device with six degrees of freedom as described in claim 1, characterized in that: The end of the elastic component away from the slider (401) is connected to a guide rod (7), which is mounted on the surface of the static platform (1).

5. A passive compliant docking aid device with six degrees of freedom as described in any one of claims 1-4, characterized in that: The surface of the moving platform (2) is connected to a venting connector, and the surface of the top plate (102) of the stationary platform (1) is connected to an execution component of an active docking mechanism. The active docking mechanism and the passive docking mechanism cooperate to dock.

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