Variable-rigidity pneumatic rotary joint based on rigid-flexible coupling structure
Through the variable stiffness pneumatic rotary joint with a rigid-flexible coupling structure, the problems of insufficient output force and limited rotation range of soft actuators in extreme environments are solved, and high-precision rotation control and stiffness adjustment are achieved, which is suitable for high-performance robot systems under complex or extreme working conditions.
Patent Information
- Application Number
- CN202511015673.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-07-23
- Publication Date
- 2025-09-19
AI Technical Summary
Existing soft actuators have problems such as insufficient output force, limited rotation range, complex modeling and uncontrollable deformation in extreme environments, making it difficult to meet the application requirements of robots in complex or extreme environments.
A variable stiffness pneumatic rotary joint based on a rigid-flexible coupling structure is adopted. By symmetrically arranging two torsion modules and skeleton arm components, the pressure difference and pressure sum of the pneumatic muscle are used to control the rotation angle and stiffness. The outer single-degree-of-freedom parallel component prevents the pneumatic muscle from lateral bending, thereby realizing the adjustment of the rotation angle and stiffness.
It achieves high-precision rotation control and stiffness adjustment in extreme environments, has excellent flexibility and impact resistance, is suitable for a variety of special operation scenarios, overcomes the shortcomings of existing technologies, and improves modeling accuracy and output torque.
Smart Images
Figure CN120663349A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of robot actuators, and in particular to a variable-rigidity pneumatic rotary joint based on a rigid-flexible coupling structure. Background Art
[0002] With technological advancements and the development of artificial intelligence, the application environments faced by robots are becoming increasingly complex. Extreme conditions such as nuclear radiation, strong magnetic fields, and flammable and explosive environments place higher demands on robot structure and performance. To cope with these environmental hazards, traditional motors typically require shielding, reinforcement, and sealing of electronic components. This not only increases design costs, system quality requirements, and system complexity, but also hinders maintenance and fault tolerance. Furthermore, vibration and temperature fluctuations can weaken sealing and reduce system reliability.
[0003] In contrast, pneumatic soft actuators offer advantages such as good compliance, strong impact resistance, minimal electronic components, and low cost, making them promising for use in extreme environments. However, existing soft actuators still suffer from limited output force, restricted rotation range, complex modeling, and uncontrollable deformation, making them difficult to meet practical needs. Furthermore, pneumatic soft actuators are prone to lateral bending, reducing modeling accuracy and output torque.
[0004] Therefore, there is an urgent need to develop a pneumatic rotary joint with novel structure, rigid-flexible coupling, adjustable performance and strong adaptability to break through the application bottleneck of traditional motors and existing soft actuators in extreme environments. Summary of the Invention
[0005] Therefore, the technical problem to be solved by the present invention is to overcome the above-mentioned problems existing in the prior art.
[0006] To solve the above technical problems, the present invention provides a variable stiffness pneumatic rotary joint based on a rigid-flexible coupling structure, comprising: base; The main output shaft is coaxially arranged above the base; Two torsion modules are symmetrically arranged in an upper and lower manner; the torsion modules include a pneumatic muscle, a fixed platform, a rotating platform, a single-degree-of-freedom parallel component, and a skeleton arm component; the two ends of the pneumatic muscle are movably connected to the fixed platform and the rotating platform respectively; the single-degree-of-freedom parallel component is mounted on the pneumatic muscle, and the two ends of the single-degree-of-freedom parallel component are connected to the two ends of the pneumatic muscle; the two ends of the skeleton arm component are movably connected to the fixed platform and the rotating platform respectively, and the skeleton arm component is used to drive the rotating platform to perform coupled motion of axial movement and rotation around the axis; The fixed platforms of the two torsion modules are respectively connected to the base and the total output shaft; the rotating platforms of the two torsion modules are connected.
[0007] In one embodiment of the present invention, the skeleton arm component includes at least three skeleton arms, and the at least three skeleton arms are arranged at intervals along the circumferential direction; the skeleton arms include a first arm, a second arm and a third arm; the second arm extends along the S axis, and the S axis forms a predetermined angle with the plane where the base is located; the two ends of the second arm respectively form a revolving pair rotating around the X axis with one end of the first arm and one end of the third arm; the other end of the first arm and the other end of the third arm, one of the two forms a revolving pair with the fixed platform, and the other forms a revolving pair with the rotating platform rotating around the Z axis; the X axis is parallel to the plane where the base is located; the skeleton arm outputs a force F in the S direction and a force couple on the Y axis to the rotating platform, and the X axis, Y axis and Z axis establish a three-dimensional rectangular coordinate system.
[0008] In one embodiment of the present invention, at least three skeleton arms are evenly distributed along the circumference.
[0009] In one embodiment of the present invention, the skeleton arm is made of a composite aluminum material; the composite aluminum material includes two aluminum layers and a flexible layer sandwiched between the two aluminum layers; at the position where the rotating pair is formed, the aluminum layer is removed and connected through the flexible layer.
[0010] In one embodiment of the present invention, the single-degree-of-freedom parallel component includes a plurality of stacked single-degree-of-freedom connecting members; the single-degree-of-freedom connecting member includes two intermediate support members and a plurality of flexible telescopic members; the intermediate support member is in contact with the pneumatic muscle; the plurality of flexible telescopic members are arranged at intervals along the circumference, and the flexible telescopic members are connected between the two intermediate support members; the flexible telescopic member includes two connecting arms arranged symmetrically up and down; one end of the two connecting arms is rotatably connected, and the other end of the two connecting arms is rotatably connected to the two intermediate support members respectively.
[0011] In one embodiment of the present invention, a first channel is provided on the base; a second channel is provided on the total output shaft; two pneumatic muscles are respectively connected to one end of the first channel and one end of the second channel; the other ends of the first channel and the second channel are respectively connected to the air source.
[0012] In one embodiment of the present invention, the present application also includes an air pressure module, which includes an air pump and an air pressure regulating part; one end of the air pump is connected to the air source, and the other end is connected to the pneumatic muscle through a pipeline; the air pressure regulating part is used to adjust the pressure of the pneumatic muscle.
[0013] In one embodiment of the present invention, the housing is movably connected to the main output shaft via a pneumatic slip ring; the pneumatic slip ring includes a stator and a rotor movably connected to the stator; the main output shaft is connected to the rotor; and the stator is connected to the housing.
[0014] In one embodiment of the present invention, the present application further includes a shaft sleeve connected to the top end of the rotor, and the shaft sleeve is disposed against the upper surface of the rotor.
[0015] In one embodiment of the present invention, the torsion module further includes a pneumatic muscle connecting shaft, one end of the pneumatic muscle is connected to the pneumatic muscle connecting shaft, and the pneumatic muscle connecting shaft is movably connected to the rotating platform.
[0016] The above technical solution of the present invention has the following advantages over the prior art: The variable stiffness pneumatic rotary joint based on the rigid-flexible coupling structure described in the present invention is a pneumatic rotary joint with variable stiffness. The present invention arranges two torsion modules symmetrically, and the skeleton arm component is used to drive the rotary platform to perform coupled motion of axial movement and rotation around the axis, and the motion of the total output shaft in the axial direction is restricted, thereby realizing the angle control and stiffness adjustment of the rotary joint. Among them, the rotation angle of the present application is controlled by the pressure difference of the two pneumatic muscles, and the stiffness of the present application is controlled by the sum of the pressures of the two pneumatic muscles. The two do not interfere with each other and have excellent flexibility and impact resistance. The overall structure is lightweight and compact, and the manufacturing process is simple. It is suitable for high-performance robot systems in various extreme environments and has broad engineering application prospects. In summary, the present rotary joint has both stiffness adjustment and rotation control functions, has excellent mechanical properties and environmental adaptability, can achieve stable and efficient rotation and torque output under complex or extreme working conditions, and is suitable for a variety of special operation scenarios. The present rotary joint overcomes the problems of insufficient output force, limited rotation range and uncontrollable deformation of the soft drive in the prior art. Secondly, the present application sets up a single-degree-of-freedom parallel component on the outer shell of the pneumatic muscle, which can prevent the pneumatic muscle from bending laterally under the action of high-pressure gas, thereby improving the modeling accuracy and output torque of the pneumatic rotary joint. BRIEF DESCRIPTION OF THE DRAWINGS
[0017] In order to make the content of the present invention more clearly understood, the present invention is further described in detail below based on specific embodiments of the present invention in conjunction with the accompanying drawings, wherein: Figure 1 Schematic diagram of a variable stiffness pneumatic rotary joint based on a rigid-flexible coupling structure in a preferred embodiment of the present invention; Figure 2 yes Figure 1 The front view of the variable stiffness pneumatic rotary joint based on the rigid-flexible coupling structure is shown; Figure 3 yes Figure 2 AA section view; Figure 4 yes Figure 1 The schematic diagram of the structure of the variable stiffness pneumatic rotary joint based on the rigid-flexible coupling structure without the shell is shown; Figure 5 yes Figure 4 The main view; Figure 6 yes Figure 5 BB cross-sectional view; Figure 7 yes Figure 1 The exploded diagram of the variable stiffness pneumatic rotary joint based on the rigid-flexible coupling structure is shown; Figure 8 yes Figure 1 The schematic diagram of the structure of the single-degree-of-freedom connection in the variable stiffness pneumatic rotary joint based on the rigid-flexible coupling structure is shown; Description of the accompanying drawings: 100, base; 110, first side hole; 120, first center hole; 200, total output shaft; 210, second side hole; 220, second center hole; 300, torsion module; 300a, first torsion module; 300b, second torsion module; 310, pneumatic muscle; 310a, first pneumatic muscle; 310b, second pneumatic muscle; 320, fixed platform; 320a, first fixed platform; 320b, second fixed platform; 330, rotating platform; 330a, first rotating platform; 330b, second rotating platform; 340, single-degree-of-freedom parallel component; 341, intermediate support member; 342, flexible telescopic member; 3421, connecting arm; 350, skeleton arm member; 350a, first skeleton arm member; 350b, second skeleton arm member; 351, skeleton arm; 3511, first arm; 3512, second arm; 3513, third arm; 360, pneumatic muscle connecting shaft; 370, rolling bearing; 400, housing; 410, lower through hole; 420, upper through hole; 500, pneumatic slip ring; 510, stator; 520, rotor; 600. Bushing. DETAILED DESCRIPTION
[0018] The present invention will be further described below with reference to the accompanying drawings and specific embodiments so that those skilled in the art can better understand the present invention and implement it. However, the embodiments are not intended to limit the present invention.
[0019] Reference Figures 1 to 8 As shown, an embodiment of the present invention provides a variable stiffness pneumatic rotary joint based on a rigid-flexible coupling structure, comprising: Base 100; The main output shaft 200 is coaxially arranged above the base 100; Two torsion modules 300 are symmetrically arranged in a vertical direction. The torsion modules 300 include a pneumatic muscle 310, a fixed platform 320, a rotating platform 330, a single-degree-of-freedom parallel component 340, and a skeleton arm component 350. The pneumatic muscle 310 has a cavity inside. The two ends of the pneumatic muscle 310 are movably connected (e.g., rotatably connected) to the fixed platform 320 and the rotating platform 330, respectively. The single-degree-of-freedom parallel component 340 is mounted on the pneumatic muscle 310, and the two ends of the single-degree-of-freedom parallel component 340 are connected to the two ends of the pneumatic muscle 310. The two ends of the skeleton arm component 350 are movably connected (e.g., rotatably connected) to the fixed platform 320 and the rotating platform 330, respectively. The skeleton arm component 350 is used to drive the rotating platform 330 to perform a coupled motion of axial translation and rotation about the axis (i.e., spiral motion). The two torsion modules 300 rotate in the same direction. The pneumatic muscle 310 is used to drive the torsion modules 300 to move.
[0020] The fixed platforms 320 of the two torsion modules 300 are connected to the base 100 and the main output shaft 200 respectively; the rotating platforms 330 of the two torsion modules 300 are connected.
[0021] The rigidity of the rotary joint is related to the sum of the pressures of the two torsion modules 300, so the rigidity of the rotary joint can be adjusted by controlling the sum of the pressures of the two pneumatic muscles 310. The higher the sum of the pressures of the two torsion modules 300, the "harder" the pneumatic muscles 310 are, and the stronger the support provided; the lower the sum of the pressures of the two torsion modules 300, the "softer" the pneumatic muscles 310 are, and the weaker the support. The pressure difference between the two pneumatic muscles 310 is related to the rotation angle output by the rotary joint, so the pressure difference between the two pneumatic muscles 310 can be controlled to adjust the rotation angle output by the rotary joint. It can be seen that the torsion skeleton of the torsion module 300 has both rigid support capabilities and flexible torsion characteristics, and this application is a rigid-flexible coupling structure.
[0022] Because the pneumatic muscle 310 drives the torsion module 300 under high pressure while being subjected to the pressure of the torsion module 300, and the elongation of the pneumatic muscle 310 is limited, the high-pressure gas inside the pneumatic muscle 310 drives the pneumatic muscle 310 to bend laterally, especially in the middle part of the pneumatic muscle 310, where the offset is the largest, resulting in a decrease in the total output force of the pneumatic muscle 310 and affecting its modeling accuracy. Therefore, the single-degree-of-freedom parallel component 340 of the present application can prevent the pneumatic muscle 310 from bending laterally under the action of high-pressure gas, thereby improving the modeling accuracy and output torque of the rotary joint.
[0023] Specifically, the present invention arranges two torsion modules 300 symmetrically, and the skeleton arm component 350 is used to drive the rotating platform 330 to perform coupled motion of axial movement and rotation around the axis, and the movement of the total output shaft 200 in the axial direction is restricted, thereby realizing the angle control and stiffness adjustment of the rotary joint. Among them, the rotation angle of the present application is controlled by the pressure difference of the two pneumatic muscles 310, and the stiffness of the present application is controlled by the sum of the pressures of the two pneumatic muscles 310. The two do not interfere with each other and have excellent flexibility and impact resistance; the overall structure is lightweight and compact, and the manufacturing process is simple. It is suitable for high-performance robot systems in various extreme environments and has broad engineering application prospects. In summary, the present rotary joint has both stiffness adjustment and rotation control functions, has excellent mechanical properties and environmental adaptability, can achieve stable and efficient rotation and torque output under complex or extreme working conditions, and is suitable for a variety of special operation scenarios. In addition, the present rotary joint overcomes the problems of insufficient output force, limited rotation range, complex modeling, and irregular deformation of the soft drive in the prior art. Secondly, the present application provides a single-degree-of-freedom parallel component 340 outside the pneumatic muscle 310, which can prevent the pneumatic muscle 310 from bending laterally under the action of high-pressure gas, thereby improving the modeling accuracy and output torque of the pneumatic rotary joint.
[0024] The rotation angle θ output by the rotary joint (i.e., the rotation angle of the total output shaft 200) is achieved by the movement of the two torsion modules 300. The rotation angles of the rotating platforms 330 of the two torsion modules 300 relative to the fixed platform 320 are respectively θ1 and θ2, where θ=θ1+θ2.
[0025] Furthermore, the present application also includes a shell 400 , which is covered on the torsion module 300 , one end of the shell 400 is connected to the base 100 , and the other end is movably connected to the main output shaft 200 .
[0026] Specifically, the housing 400 is provided in this embodiment to protect the torsion module 300 therein, preventing dust and other impurities from entering and damaging the torsion module 300. In addition, the torsion module 300 and other structures are prevented from being exposed to the outside and scratching personnel during movement.
[0027] Furthermore, the skeleton arm component 350 includes at least three (for example, three; for example, four) skeleton arms 351, and the at least three skeleton arms 351 are arranged at intervals along the circumferential direction; the skeleton arms 351 include a first arm 3511, a second arm 3512 and a third arm 3513; the second arm 3512 extends along the S axis, and the S axis forms a predetermined angle with the plane where the base 100 is located; the two ends of the second arm 3512 are respectively connected to one end of the first arm 3511 and the third arm 3513. One end of the arm 3513 forms a revolving pair that rotates around the X-axis; the other end of the first arm 3511 and the other end of the third arm 3513, one of which forms a revolving pair with the fixed platform 320, and the other forms a revolving pair with the rotating platform 330 that rotates around the Z-axis; the X-axis is parallel to the plane where the base 100 is located; the skeleton arm 351 outputs a force F in the S direction and a couple M on the Y-axis to the rotating platform 330, and the X-axis, Y-axis and Z-axis establish a three-dimensional rectangular coordinate system.
[0028] Specifically, this embodiment realizes the output of force F and couple M through three rotatably connected skeleton arms 351, and has a simpler structure and is more practical.
[0029] Furthermore, at least three skeleton arms 351 are evenly distributed along the circumferential direction.
[0030] Specifically, the skeleton arms 351 of this embodiment are evenly distributed to avoid unbalanced loading during movement, preventing problems such as accelerated local wear caused by excessive force on one side, reduced positioning accuracy of the motion mechanism, and accelerated component aging. This ensures more even force distribution, ensures positioning accuracy, increases service life, provides more stable operation, and reduces the risk of failure.
[0031] Furthermore, the skeleton arm 351 is made of a composite aluminum material; the composite aluminum material comprises two aluminum layers and a flexible layer sandwiched between them. At the locations forming the revolute pair, the aluminum layers are removed and connected via the flexible layer. In some embodiments, the single-degree-of-freedom parallel component 340 and the skeleton arm 351 are made of the same material. The flexible layer is made of a flexible material such as polypropylene (PP) and is bendable.
[0032] Specifically, the skeleton support arm 351 of this embodiment is made of composite aluminum material, which is lightweight and convenient for processing and forming of the rotating sub-position.
[0033] The pneumatic muscle 310 is a corrugated flexible structure, and the pneumatic muscle 310 is made of 3D printed TPU material.
[0034] Furthermore, the single-degree-of-freedom parallel component 340 includes a plurality of stacked single-degree-of-freedom connectors; the single-degree-of-freedom connectors include two intermediate support members 341 and a plurality of flexible telescopic members 342; the intermediate support member 341 contacts the pneumatic muscle 310 to prevent the pneumatic muscle from bending laterally; the plurality of flexible telescopic members 342 are arranged at circumferential intervals, and the flexible telescopic members 342 are connected between the two intermediate support members 341; the flexible telescopic member 342 includes two connecting arms 3421 symmetrically arranged up and down; one end of the two connecting arms 3421 is rotatably connected, and the other end of the two connecting arms 3421 is rotatably connected to the two intermediate support members 341 respectively.
[0035] Specifically, the single-degree-of-freedom parallel component 340 has a passive single-degree-of-freedom telescopic capability, which is controllable, has a simple structure, and operates stably and reliably, and is easy to process and form using a composite aluminum material.
[0036] Furthermore, a first channel is provided on the base 100; a second channel is provided on the total output shaft 200; two pneumatic muscles 310 are respectively connected to one end of the first channel and one end of the second channel; the other ends of the first channel and the second channel are respectively connected to the air source (external air source) through air pipes.
[0037] In some embodiments, the first channel includes a first side hole 110 and a first central hole 120 that are interconnected. The first central hole 120 is coaxially disposed on the base 100, and the first side hole 110 is disposed on a sidewall of the base 100. The first central hole 120 is connected to the pneumatic muscle 310, and the first central hole 120 is connected to the first side hole 110. The housing 400 is provided with a lower through hole 410 corresponding to the first side hole 110. The first side hole 110 is connected to an external air source through the lower through hole 410. In this way, the pneumatic muscle 310 is sequentially connected to the first central hole 120, the first side hole 110, the lower through hole 410, and the external air source via the airway.
[0038] In some embodiments, the second channel includes a second side hole 210 and a second center hole 220 that are interconnected. The second center hole 220 is located on the side of the main output shaft 200 facing the main output shaft 200, and the second side hole 210 is located on the sidewall of the main output shaft 200. The second center hole 220 is connected to the pneumatic muscle 310, and the second center hole 220 is connected to the second side hole 210. The second side hole 210 is connected to the air outlet hole on the rotor 520 of the pneumatic slip ring 500, and the air outlet hole is connected to the air inlet hole on the stator 510 of the pneumatic slip ring 500. The housing 400 is provided with an upper through hole 420 corresponding to the air inlet hole, and the air inlet hole is connected to an external air source through the upper through hole 420. In this way, the pneumatic muscle 310 is connected to the second center hole 220, the second side hole 210, the air outlet hole, the air inlet hole, the upper through hole 420, and the external air source in sequence through the air pipe.
[0039] Specifically, since the upper and lower ends of the present invention are fixed ends and the middle position is the moving end, if air is supplied to the two pneumatic muscles 310 from the middle position, the trachea will be entangled. In addition, a relatively large avoidance hole needs to be opened in the shell 400 to facilitate the layout of the trachea, which reduces the overall structural rigidity of the present invention. However, the present invention supplies air to the two pneumatic muscles 310 from the upper and lower fixed ends, which solves the problem of tracheal entanglement on the one hand. On the other hand, the shell 400 only needs to have through holes corresponding to the trachea, which does not affect the overall structural rigidity of the present invention.
[0040] Furthermore, the present application also includes an air pressure module, which includes an air pump and an air pressure regulating unit; one end of the air pump is connected to the air source, and the other end is connected to the pneumatic muscle 310 through a pipeline; the air pressure regulating unit includes an execution end and a control end; the execution end is arranged on the pipeline, the control end is electrically connected to the execution end, and the control end controls the execution end, which is used to adjust the pressure of the pneumatic muscle 310.
[0041] Specifically, the control end calculates the pressure difference ΔP between the two pneumatic muscles 310 in real time based on the set target angle, using a PID or fuzzy control strategy, to precisely control the rotation angle of the total output shaft 200. The control end then controls the execution end to precisely control the air pressure values of the two pneumatic muscles 310, thereby rotating the rotary joint to the target angle. Thus, the present application can automatically and precisely control the rotation angle of the total output shaft 200 and adjust the stiffness of the rotary joint.
[0042] The stiffness of this rotary joint can be achieved by adjusting the total air pressure of the two pneumatic muscles 310: when the air pressure of the two torsion modules 300 increases at the same time, the overall stiffness of the rotary joint will increase, and the ability to resist deformation due to external forces will be enhanced, so the application will be less likely to deform when subjected to external forces; conversely, when the air pressure of the two torsion modules 300 decreases at the same time, the overall stiffness of the rotary joint will decrease, and the joint will be more flexible and more agile. In this way, in tasks requiring high-precision positioning, the stability of the rotary joint can be enhanced by increasing the air pressure of the two pneumatic muscles 310; and in scenarios requiring flexible movement, reducing the air pressure of the two pneumatic muscles 310 will help improve the compliance and adjustability of the joint.
[0043] Furthermore, the housing 400 is movably connected to the main output shaft 200 via a pneumatic slip ring 500. The pneumatic slip ring 500 includes a stator 510 and a rotor 520 movably connected to the stator 510. The main output shaft 200 is connected to the rotor 520, for example, by an interference fit between the inner rings of the main output shaft 200 and the rotor 520. The stator 510 is connected to the housing 400, for example, by being fixedly connected by screws.
[0044] Specifically, in this embodiment, the pneumatic slip ring 500 is used to realize the rotational connection between the main output shaft 200 and the housing 400, thereby facilitating the connection between the pneumatic muscle 310 and the external air source.
[0045] Furthermore, the present application also includes a shaft sleeve 600 connected to the top end of the rotor 520 , and the shaft sleeve 600 is disposed against the upper surface of the rotor 520 .
[0046] Specifically, the sleeve 600 of this embodiment is connected to the top of the rotor 520, which can limit the movement of the main output shaft 200 along the axis toward the base 100, thereby preventing the main output shaft 200 from moving along the axis toward the interior of the application under negative pressure. Therefore, this application is also applicable to negative pressure applications.
[0047] Furthermore, the torsion module 300 includes a pneumatic muscle connecting shaft 360, to which one end of the pneumatic muscle 310 is connected. The pneumatic muscle connecting shaft 360 is movably connected to the rotating platform 330 via a rolling bearing 370. In some embodiments, a groove is provided on one side of the rotating platform 330, into which the rolling bearing 370 is mounted, and the pneumatic muscle connecting shaft 360 is connected to the inner ring of the rolling bearing 370. In some possible implementations, the pneumatic muscle connecting shaft 360 and the inner ring of the rolling bearing 370 have an interference fit.
[0048] Specifically, the pneumatic muscle 310 is connected to the rotating platform 330 through the pneumatic muscle connecting shaft 360, and the structure is more stable and reliable.
[0049] The various components of this application are integrally formed through 3D printing; this application takes into account both lightweight structure and reliable performance, and is suitable for use in platforms such as rigid-flexible coupling robots, collaborative robots, and medical robots.
[0050] The rotary joint achieves motion and force output by controlling the inflation and deflation of two pneumatic muscles 310 .
[0051] The principles of this application movement are as follows: For ease of description, the two torsion modules 300 are divided into a first torsion module 300a and a second torsion module 300b. The first torsion module 300a includes a first pneumatic muscle 310a, a first rotating platform 330a, a first skeleton arm component 350a, and a first fixed platform 320a. The second torsion module 300b includes a second pneumatic muscle 310b, a second rotating platform 330b, a second skeleton arm component 350b, and a second fixed platform 320b.
[0052] When the first pneumatic muscle 310a is inflated, it extends and propels the first rotating platform 330a. Because the first rotating platform 330a is constrained by the first skeletal arm assembly 350a, it simultaneously moves axially and rotates counterclockwise relative to the first fixed platform 320a. This means that the first torsion module 300a produces a spiral motion. Simultaneously, the extension of the first torsion module 300a compresses the second torsion module 300b. Constrained by the second skeletal arm assembly 350b, the second rotating platform 330b simultaneously moves axially and rotates counterclockwise relative to the second fixed platform 320b. The axial motion of the main output shaft 200 is restricted by the housing 400. Therefore, due to the coordinated action of the first and second torsion modules 300a, the main output shaft 200 only has rotational freedom. The total output shaft 200 superimposes the counterclockwise rotation angle of the first torsion module 300a and the counterclockwise rotation angle of the second torsion module 300b to achieve a total counterclockwise rotation output.
[0053] Conversely, when the second pneumatic muscle 310b is inflated, it extends and pushes the second rotating platform 330b to move. Because the second rotating platform 330b is constrained by the second skeletal arm component 350b, it moves axially while rotating clockwise relative to the second fixed platform 320b. Simultaneously, the extension of the second torsion module 300b compresses the first torsion module 300a. The first rotating platform 330a, constrained by the first skeletal arm component 350a, moves axially relative to the first fixed platform 320a while rotating clockwise. The total output shaft 200 superimposes the clockwise rotation angles of the first torsion module 300a and the second torsion module 300b, achieving a total clockwise rotation output.
[0054] It can be seen that the present application can output positive and negative rotational kinetic energy.
[0055] Obviously, the above embodiments are merely examples for clarity of explanation and are not intended to limit the implementation methods. Those skilled in the art will appreciate that other variations or modifications can be made based on the above description. It is not necessary and impossible to enumerate all implementation methods here. Obvious variations or modifications arising therefrom remain within the scope of protection of the present invention.
Claims
1. A variable stiffness pneumatic rotary joint based on a rigid-flexible coupling structure, characterized by: include: base; A main output shaft is arranged above the base; Two torsion modules are symmetrically arranged in an upper and lower manner; the torsion module includes a pneumatic muscle, a fixed platform, a rotating platform, a single-degree-of-freedom parallel component and a skeleton arm component; the two ends of the pneumatic muscle are respectively movably connected to the fixed platform and the rotating platform; the single-degree-of-freedom parallel component is sleeved on the pneumatic muscle, and the two ends of the single-degree-of-freedom parallel component are connected to the two ends of the pneumatic muscle; the two ends of the skeleton arm component are respectively movably connected to the fixed platform and the rotating platform, and the skeleton arm component is used to drive the rotating platform to perform coupled motion of axial movement and rotation around the axis; The fixed platforms of the two torsion modules are respectively connected to the base and the total output shaft; the rotating platforms of the two torsion modules are connected.
2. The variable stiffness pneumatic rotary joint based on a rigid-flexible coupling structure according to claim 1, characterized in that: The skeleton arm component includes at least three skeleton arms, and the at least three skeleton arms are arranged at intervals along the circumferential direction; the skeleton arm includes a first arm, a second arm and a third arm; the second arm extends along the S axis, and the S axis forms a predetermined angle with the plane where the base is located; the two ends of the second arm respectively form a revolving pair rotating around the X axis with one end of the first arm and one end of the third arm; the other end of the first arm and the other end of the third arm, one of the two forms a revolving pair with the fixed platform, and the other forms a revolving pair with the rotating platform around the Z axis; the X axis is parallel to the plane where the base is located; the skeleton arm outputs a force F in the S direction and a force couple on the Y axis to the rotating platform, and the X axis, Y axis and Z axis establish a three-dimensional rectangular coordinate system.
3. The variable stiffness pneumatic rotary joint based on a rigid-flexible coupling structure according to claim 2, characterized in that: At least three of the skeleton arms are evenly distributed along the circumference.
4. The variable stiffness pneumatic rotary joint based on a rigid-flexible coupling structure according to claim 2, characterized in that: The skeleton support arm is made of a composite aluminum material; the composite aluminum material includes two aluminum layers and a flexible layer sandwiched between the two aluminum layers; at the position where the rotating pair is formed, the aluminum layer is removed and then connected through the flexible layer.
5. The variable stiffness pneumatic rotary joint based on a rigid-flexible coupling structure according to claim 1, characterized in that: The single-degree-of-freedom parallel component includes multiple stacked single-degree-of-freedom connecting parts; the single-degree-of-freedom connecting part includes two intermediate support parts and multiple flexible telescopic parts; the intermediate support part is in contact with the pneumatic muscle; multiple flexible telescopic parts are arranged at intervals along the circumferential direction; the flexible telescopic part is connected between the two intermediate support parts; the flexible telescopic part includes two connecting arms arranged symmetrically up and down; one end of the two connecting arms is rotatably connected, and the other end of the two connecting arms is rotatably connected to the two intermediate support parts respectively.
6. The variable stiffness pneumatic rotary joint based on a rigid-flexible coupling structure according to claim 1, characterized in that: A first channel is provided on the base; a second channel is provided on the total output shaft; the two pneumatic muscles are respectively connected to one end of the first channel and one end of the second channel; the other ends of the first channel and the second channel are respectively connected to an air source.
7. The variable stiffness pneumatic rotary joint based on a rigid-flexible coupling structure according to claim 1, characterized in that: It also includes an air pressure module, which includes an air pump and an air pressure regulating part; one end of the air pump is connected to the air source, and the other end is connected to the pneumatic muscle through a pipeline; the air pressure regulating part is used to adjust the pressure of the pneumatic muscle.
8. The variable stiffness pneumatic rotary joint based on a rigid-flexible coupling structure according to claim 1, characterized in that: It also includes a shell covered on the torsion module; the shell is movably connected to the total output shaft through a pneumatic slip ring; the pneumatic slip ring includes a stator and a rotor movably connected to the stator; the total output shaft is connected to the rotor; and the stator is connected to the shell.
9. The variable stiffness pneumatic rotary joint based on a rigid-flexible coupling structure according to claim 8, characterized in that: It also includes a shaft sleeve connected to the top end of the rotor, and the shaft sleeve is arranged against the upper surface of the rotor.
10. The variable stiffness pneumatic rotary joint based on a rigid-flexible coupling structure according to claim 1, characterized in that: The torsion module further includes a pneumatic muscle connecting shaft, one end of the pneumatic muscle is connected to the pneumatic muscle connecting shaft, and the pneumatic muscle connecting shaft is movably connected to the rotating platform.