Three-degree-of-freedom joint and its flexible variable-rigidity space manipulator

Abstract

A three-degree-of-freedom joint and a flexible variable-rigidity space robot arm thereof, comprising: a moving structure and a torsion structure fixedly arranged on a fixed supporting structure, and a transmission structure rotatably arranged on the fixed supporting structure and respectively in contact with the moving structure and the torsion structure; the flexible variable-rigidity space robot arm comprises: a plurality of three-degree-of-freedom joints and a main structure. The present invention is based on a foldable structure with flexible variable-rigidity characteristics. Through the design of the joint structure, the movement of the joint on the main structure and the bending and torsion of the main structure are achieved, thereby adjusting the configuration of the main structure. The joint action of multiple joints can complete the realization of a complex configuration of the main structure, thereby increasing the number of degrees of freedom of the robot arm, thereby having higher flexibility when capturing space debris.

Description

Technical Field

[0001] The present invention relates to a technology in the field of space operation, in particular to a three-degree-of-freedom joint and a flexible variable-rigidity space manipulator thereof. Background Art

[0002] With the development of human space exploration activities, the amount of space debris generated has gradually increased, posing a threat to the safety of on-orbit spacecraft and space workers. Transferring existing space debris through active removal is of great significance to maintaining a sustainable space exploration environment. Existing space debris capture devices include flying nets, harpoons, rigid robotic arms, etc. Among them, flexible flying nets, harpoons and other capture methods have the defect of being non-reusable. Due to its structural limitations, rigid robotic arms are difficult to capture targets at a distance. In addition, some foldable structures are also widely used in space technology. Some foldable structures have the characteristics of flexibility and variable stiffness, and can have a wide range of action, but there are few applications of applying them to the design of space robotic arms and improving the flexibility of robotic arms through their structural characteristics. Summary of the invention

[0003] In view of the defects of the existing space robot arms used for capturing space debris, such as the limited range of action and insufficient flexibility, the present invention proposes a three-degree-of-freedom joint and a flexible variable-rigidity space robot arm. Based on a foldable structure with the characteristics of flexible variable stiffness, the joint structure is designed to realize the movement of the joint on the main structure and the bending and twisting of the main structure, thereby adjusting the configuration of the main structure. The joint action of multiple joints can realize the complex configuration of the main structure, increase the number of degrees of freedom of the robot arm, and thus have higher flexibility when capturing space debris.

[0004] The present invention is achieved through the following technical solutions:

[0005] The invention relates to a three-degree-of-freedom joint, comprising: a moving structure and a torsion structure fixedly arranged on a fixed support structure, and a transmission structure rotatably arranged on the fixed support structure and contacting the moving structure and the torsion structure respectively.

[0006] The present invention relates to a flexible variable-rigidity spatial robot arm based on the above-mentioned three-degree-of-freedom joint, comprising: a plurality of three-degree-of-freedom joints and a main structure, wherein: the main structure sequentially controls each three-degree-of-freedom joint through a torsion limit plate, an active rotating roller and a driven rotating roller, and a rotation limit plate to independently realize torsion action, movement action, rotation action and bending deformation action to realize multi-joint coordinated configuration adjustment and change.

[0007] Technical Effects

[0008] The freedom of movement of the present invention is achieved by the friction between the roller pair that rotates in opposite directions and the hyperbolic structure of the main body of the mechanical arm synchronously clamped inside the joint. The freedom of rotation is achieved by the contact between the rotation limit plate and the hyperbolic structure of the main body of the mechanical arm driven by the motor. The freedom of torsion is achieved by the torsion limit plate that passes through the hyperbolic structure of the main body of the mechanical arm driven by the motor to rotate, and the contact with the torsion limit plate in the torsion direction of the main structure. The device acts on the main body of the hyperbolic structure mechanical arm to achieve the movement of the joint on the main body of the mechanical arm, thereby adjusting the relative length of each section of the mechanical arm. The effect of the above-mentioned freedom of rotation of the joint can achieve the bending of the main structure along the clamping point of the roller pair inside the joint. The effect of the above-mentioned freedom of torsion of the joint can achieve the torsion rotation of the main structure along the extension direction. The combined effect of the three degrees of freedom of movement, rotation and torsion can achieve the change of the configuration of the main structure in the joint action part. The synergistic effect of multiple joints can achieve the adjustment of the complex configuration of the main structure, so as to facilitate the realization of complex capture tasks in space environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 It is a schematic diagram of the overall structure of the present invention;

[0010] Figure 2 It is a schematic diagram of the working principle of the joint torsion structure;

[0011] Figure 3 This is a schematic diagram of the torsion effect of the main structure;

[0012] Figure 4 It is a schematic diagram of the assembly of a torsion limiting plate, a torsion transmission gear, a torsion driving element, a torsion driving element fixing member, and a first supporting member;

[0013] Figure 5 It is an exploded view of some parts of the torsion limit plate, the torsion transmission gear, the torsion drive element, the torsion drive element fixing part, and the first support member;

[0014] Figure 6 It is a schematic diagram of the working principle of the joint moving structure;

[0015] Figure 7 An exploded view of some parts of the active rotating roller, the driven rotating roller, the fixed frame, the bearing, the first supporting member, and the second supporting member;

[0016] Figure 8 It is a schematic diagram of the working principle of the joint transmission structure;

[0017] Fig. 9 It is a schematic diagram of the structure of the torsion limit plate;

[0018] Fig.10 This is a schematic diagram of the synergistic effect of multiple joints of the robotic arm;

[0019] In the figure: 1 torsion limit plate, 2 torsion transmission gear, 3 torsion drive element, 4 torsion drive element fixing part, 5 first support part, 6 second support part, 7 active rotating roller, 8 driven rotating roller, 9 mobile driving element, 10 mobile driving element fixing part, 11 bearing, 12 fixed frame, 13 rotation limit plate, 14 rotation transmission gear, 15 rotation drive element, 16 main structure, 17 flexible variable stiffness space manipulator three-degree-of-freedom joint, 18 base. DETAILED DESCRIPTION

[0020] like Figure 1 As shown, this embodiment relates to a three-degree-of-freedom joint, including: a moving structure and a torsion structure fixedly arranged on a fixed support structure, and a transmission structure rotatably arranged on the fixed support structure and respectively in contact with the moving structure and the torsion structure.

[0021] like Figure 1 and Figure 7 As shown, the fixed support structure includes: a first support member 5, a second support member 6 and a fixed frame 12 connected in sequence, wherein: the first support member 5 is provided with a torsion drive element fixing member 4 for setting the torsion structure, and the fixed frame 12 is provided with a mobile drive element fixing member 10 for setting the mobile structure.

[0022] The fixed frame 12 includes four sub-frames 1201 - 1204 .

[0023] like Figures 1 to 5 As shown, the torsion structure includes: a torsion limiting plate 1 fixedly connected to the fixed supporting structure, and a torsion driving element 3 and a torsion transmission gear 2 arranged on the torsion limiting plate 1, wherein: the torsion driving element 3 is arranged on the first support member 5, the torsion limiting plate 1 is respectively connected to the first support member 5 and the second support member 6, and the torsion driving element 3 is connected to the torsion transmission gear 2 to directly drive the rotation of the torsion transmission gear 2.

[0024] like Fig. 9 As shown, the torsion limiting plate 1 comprises: a gear-shaped torsion limiting structure 101, an upper fixed structure 102 and a lower fixed structure 103, wherein: the profile of the gear-shaped torsion limiting structure 101 is a tooth shape corresponding to the torsion driving gear 2, an arc-shaped gap is provided in the middle for the main structure 16 to pass through, and arc-shaped limiting grooves corresponding to the upper fixed structure 102 and the lower fixed structure 103 are provided on the upper and lower surfaces respectively. When the upper fixed structure 102 and the lower fixed structure 103 are superimposed, the arc-shaped protrusion of the fixed structure cooperates with the arc-shaped limiting groove of the gear-shaped torsion limiting structure 101, so that the gear-shaped torsion limiting structure 101 can be fully constrained in the axial and radial directions while maintaining the rotation ability.

[0025] The torsion transmission gear 2 drives the gear-shaped torsion limiting structure 101 to rotate.

[0026] like Figure 6 and Figure 7 As shown, the mobile structure includes: a mobile driving element 9, an active rotating roller 7 and a driven rotating roller 8, wherein: the active rotating roller 7 and the driven rotating roller 8 are rotatably arranged on a fixed frame 12 of a fixed support structure through bearings 11 respectively, and the mobile driving element 9 is arranged in a first sub-frame 1201 of the fixed frame 12 through a mobile driving element fixing part 10 and is connected to the active transmission roller 7.

[0027] The active transmission roller 7 is implemented by an active transmission gear 701 in this embodiment; the driven rotating roller 8 is implemented by a driven transmission gear 801 in this embodiment, and the active transmission gear 701 drives the meshing driven transmission gear 801 to rotate, thereby realizing the synchronous reverse rotation of the driven rotating roller 8.

[0028] like Figure 8 As shown, the transmission structure includes: a rotation limit plate 13, a rotation drive element 15 and a rotation transmission gear 14 arranged on the fixed support structure, wherein: the rotation drive element 15 is specifically arranged on the second support member 6 and is connected to the rotation transmission gear 14, directly driving the rotation of the rotation transmission gear 14; one end of the rotation limit plate 13 is a local gear structure and is meshed with the rotation transmission gear 14, and the rotation transmission gear 14 drives the rotation of the rotation limit plate 13.

[0029] like Fig.10 As shown, a flexible variable-rigidity spatial robot arm based on the above-mentioned three-degree-of-freedom joint involved in this embodiment includes: a plurality of three-degree-of-freedom joints and a main structure 16, wherein: the main structure 16 sequentially controls the torsion limit plate 1, the active rotating roller 7 and the driven rotating roller 8, and the rotation limit plate 13 of each three-degree-of-freedom joint, and realizes the configuration adjustment and change of multi-joint coordination by independently realizing torsion action, movement action, rotation action and bending deformation action of each three-degree-of-freedom joint.

[0030] like Figure 2 and Figure 3 As shown, the twisting action is achieved by the main structure 16 passing through the limiting gap of the torsion limiting plate 1, under the joint action of the rotation of the rotating gear-shaped torsion limiting structure 101 and the clamping of the active rotating roller 7 and the driven rotating roller 8. Specifically, there is a misalignment between the cross-section of the main structure 16 before the action of the torsion limiting plate 1 and the cross-section of the main structure 16 after the clamping action of the active rotating roller 7 and the driven rotating roller 8, showing the torsion effect of the main structure 16.

[0031] like Figure 6As shown, the moving action is achieved by the rotation of the active rotating roller 7 and the driven rotating roller 8, so that the relative position of the main structure 16 and the three-degree-of-freedom joint as a whole changes under the action of friction. Specifically, under the clamping action of the active rotating roller 7 and the driven rotating roller 8 on the main structure 16, when the active rotating roller 7 and the driven rotating roller 8 rotate synchronously in opposite directions, the friction force causes the joint to move relative to the main structure 16, which is manifested as a change in the length of the main structure 16 between the joints.

[0032] The rotation action is achieved by the main structure 16 passing through the limiting gap of the rotation limiting plate 13, thereby rotating the rotation limiting plate 13.

[0033] like Figure 8 As shown, the bending deformation action means that the extension direction of the main structure 16 without the action of the rotating limit plate 13 is different from the extension direction of the main structure 16 with the action of the rotating limit plate 13, showing the bending effect of the local area of ​​the main structure 16.

[0034] like Figure 1 and Fig.10 As shown, the main structure 16 is a group of hyperbolic structural belts, each of which has a curvature in the cross section. It can maintain a certain rigidity in the absence of external force, and has the characteristic of reduced rigidity after being clamped by the active rotating roller 7 and the driven rotating roller 8. The main hyperbolic structure 16 of the robot arm passes through multiple joint structures in sequence, and the configuration of the robot arm can be adjusted under the action of multiple joints.

[0035] like Fig.10 As shown, the multi-joint coordination means that the main structure 16 extending from the base 18 passes through multiple flexible variable-rigidity spatial robotic arm three-degree-of-freedom joints 17 in sequence; when multiple joints work together, the robotic arm can achieve complex configuration changes through the respective actions of each joint's torsion, movement, and rotational degrees of freedom.

[0036] The above-mentioned specific implementation can be partially adjusted in different ways by those skilled in the art without departing from the principle and purpose of the present invention. The protection scope of the present invention shall be based on the claims and shall not be limited by the above-mentioned specific implementation. Each implementation scheme within its scope shall be subject to the constraints of the present invention.

Claims

1. A three-degree-of-freedom joint, characterized in that: include: A moving structure and a torsion structure fixedly disposed on the fixed support structure, and a transmission structure rotatably disposed on the fixed support structure and in contact with the moving structure and the torsion structure respectively; The fixed support structure comprises: a first support member, a second support member and a fixed frame connected in sequence, wherein: the first support member is provided with a torsion drive element fixing member for setting the torsion structure, and the fixed frame is provided with a mobile drive element fixing member for setting the mobile structure; The torsion structure comprises: a torsion limiting plate fixedly connected to the fixed support structure, and a torsion driving element and a torsion transmission gear arranged on the torsion limiting plate, wherein: the torsion driving element is arranged on the first support member, the torsion limiting plate is respectively connected to the first support member and the second support member, and the torsion driving element is connected to the torsion transmission gear to directly drive the rotation of the torsion transmission gear; The torsion limiting plate comprises: a gear-shaped torsion limiting structure, an upper fixed structure and a lower fixed structure, wherein: the profile of the gear-shaped torsion limiting structure is a tooth shape corresponding to the torsion driving gear, an arc-shaped gap is provided in the middle for the main structure to pass through, and arc-shaped limiting grooves corresponding to the upper fixed structure and the lower fixed structure are provided on the upper and lower surfaces respectively; when the upper fixed structure and the lower fixed structure are superimposed, the arc-shaped protrusion of the fixed structure cooperates with the arc-shaped limiting groove of the gear-shaped torsion limiting structure, so that the gear-shaped torsion limiting structure can be fully constrained in the axial direction and radial direction while maintaining the rotation ability; The mobile structure comprises: a mobile driving element, an active rotating roller and a driven rotating roller, wherein: the active rotating roller and the driven rotating roller are respectively rotatably arranged on a fixed frame of the fixed support structure through bearings, and the mobile driving element is arranged in a first subframe of the fixed frame through a mobile driving element fixing member and is connected to the active transmission roller; The main structure is a group of hyperbolic structural belts, each of which has a curvature in its cross section. It can maintain a certain rigidity in the absence of external force, and has the characteristic of reducing rigidity after being clamped by the active rotating roller and the driven rotating roller. The main hyperbolic structure of the robotic arm passes through multiple joint structures in sequence, and the configuration of the robotic arm can be adjusted under the action of multiple joints. Under the clamping action of the active rotating roller and the driven rotating roller on the main structure, the friction force causes the joints to move relative to the main structure.

2. The three-degree-of-freedom joint according to claim 1, characterized in that: The active transmission roller is realized by an active transmission gear; the driven rotating roller is realized by a driven transmission gear. The active transmission gear drives the meshing driven transmission gear to rotate, thereby realizing synchronous reverse rotation of the driven rotating roller.

3. The three-degree-of-freedom joint according to claim 1, characterized in that: The transmission structure includes: a rotation limiting plate, a rotation driving element and a rotation transmission gear arranged on a fixed supporting structure, wherein: the rotation driving element is specifically arranged on the second supporting member and connected to the rotation transmission gear, directly driving the rotation of the rotation transmission gear; one end of the rotation limiting plate is a local gear structure and is meshed with the rotation transmission gear, and the rotation transmission gear drives the rotation of the rotation limiting plate.

4. A flexible variable-rigidity space manipulator based on the three-degree-of-freedom joint described in any one of claims 1 to 3, characterized in that: include: Several three-degree-of-freedom joints and a main structure, wherein: the main structure sequentially controls each three-degree-of-freedom joint through a torsion limit plate, an active rotating roller, a driven rotating roller, and a rotating limit plate to independently realize torsion, movement, rotation, and bending deformation movements to realize multi-joint coordinated configuration adjustment and change; The twisting action is achieved by the main structure passing through the limiting gap of the torsion limiting plate, under the joint action of the rotation of the rotating gear-shaped torsion limiting structure and the clamping of the active rotating roller and the driven rotating roller. The moving action is achieved by rotating the active rotating roller and the driven rotating roller, so that the relative position of the main structure and the three-degree-of-freedom joint as a whole changes under the action of friction. The rotation action is achieved by the main structure passing through the limiting gap of the rotation limiting plate and the rotation of the rotation limiting plate; The bending deformation action means that the extension direction of the main structure without the action of the rotating limit plate is different from the extension direction of the main structure with the action of the rotating limit plate, showing the bending effect of the local area of ​​the main structure.

5. The flexible variable-rigidity space manipulator according to claim 4 is characterized in that: The twisting action is specifically: there is a misalignment between the cross section of the main structure before the twisting limit plate and the cross section of the main structure after the active rotating roller and the driven rotating roller are clamped, showing the twisting effect of the main structure; The moving action is specifically as follows: under the clamping action of the active rotating roller and the driven rotating roller on the main structure, when the active rotating roller and the driven rotating roller rotate synchronously in opposite directions, the friction force causes the joints on the main structure to move relative to each other, which is manifested as a change in the length of the main structure between the joints.

6. The flexible variable-rigidity space manipulator according to claim 4 is characterized in that: The multi-joint coordination means that the main structure extending from the base passes through multiple flexible variable-rigidity spatial robotic arm three-degree-of-freedom joints in sequence; when multiple joints work together, the robotic arm can achieve complex configuration changes through the respective actions of each joint's torsion, movement, and rotational degrees of freedom.

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