Multi-degree-of-freedom joint device with six-dimensional flexible capturing and resetting capability
By designing a six-dimensional compliant capture and reset multi-degree-of-freedom joint device, and utilizing a modular structure and composite buffering mechanism, the problem of shock buffering and attitude reset in multiple degrees of freedom directions in the prior art is solved, achieving efficient shock absorption and rapid attitude recovery, which is suitable for non-cooperative target capture in space missions.
Patent Information
- Application Number
- CN202511647389.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-11-11
- Publication Date
- 2026-01-02
AI Technical Summary
Existing joint devices have shortcomings in shock absorption and attitude recovery in multiple degrees of freedom. They are complex in structure, bulky in size and lack modular design, making it difficult to achieve efficient shock absorption and rapid attitude recovery.
A multi-degree-of-freedom joint device with six-dimensional compliant capture and reset capability was designed. Through the coordinated response of the Z-axis linear motion module, the XY-axis cross axis module and the Z-axis end module, a composite buffer mechanism is constructed by combining a magnetorheological damper and a high-stiffness spring. Automatic reset is achieved by using an electric cylinder, a reset motor and a gear mechanism.
It achieves compliant absorption of impact loads in six degrees of freedom in space, improving the system's shock resistance and attitude recovery efficiency. It is suitable for high-speed non-cooperative target acquisition missions and ensures the safety and reliability of the system structure.
Smart Images
Figure CN121245902A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of space mechanism buffering and capture technology, specifically relating to a multi-degree-of-freedom joint device with six-dimensional compliant capture and reset capabilities. Background Technology
[0002] With the continuous breakthroughs in aerospace technology, space robotic arms and non-cooperative target acquisition technology have been widely developed. Related missions have put forward requirements for joint mechanisms to provide multi-degree-of-freedom motion capabilities under high-speed impacts, while also effectively absorbing impacts and restoring attitude.
[0003] In existing research, buffering and compliant control primarily utilizes configurations of springs and dampers connected in series within the joint to absorb some energy into the buffer element, thereby reducing impact loads and protecting the actuators. Another approach involves employing adjustable damping elements, such as magnetorheological dampers, which can smoothly buffer the impact by adjusting the damping strength during contact, allowing the impact force to decay rapidly and protecting the structure. This structure has been experimentally validated in space grabbing missions, effectively reducing the impact torque on the joint at the moment of target contact and stabilizing the system's attitude. Furthermore, some studies combine compliant structures with intelligent control methods, enabling the buffer element to adjust its damping strength in real time according to mission conditions to adapt to different impact scenarios and reduce energy transfer impact.
[0004] However, most existing technologies are only applicable to unidirectional buffering and compliant control, and their arrangement is usually separate from joint drives, lacking modularity and high integration design. This results in complex system structures, large size, and difficulty in coupling control during actual deployment, leading to reduced reliability. More importantly, although springs and dampers can achieve compliant energy absorption, most solutions do not integrate a reliable attitude reset mechanism. Reset usually relies on manual or external triggering, resulting in slow attitude recovery speed and insufficient accuracy.
[0005] Therefore, there is an urgent need for a compact joint device that can cover three linear directions and three rotational directions in space, and highly integrates multi-degree-of-freedom compliant capture and reset capabilities to improve the shock absorption efficiency and attitude recovery response speed of joint systems in space missions. To this end, this invention proposes a multi-degree-of-freedom joint device with six-dimensional compliant capture and reset capabilities. Summary of the Invention
[0006] In order to solve the problem that existing joint devices do not have the ability to compliantly buffer impacts in multiple degrees of freedom during operation, this invention provides a multi-degree-of-freedom joint device with six-dimensional compliant capture and reset capability. A multi-degree-of-freedom joint device with six-dimensional compliant capture and reset capability, the multi-degree-of-freedom joint device includes a Z-axis linear motion module for absorbing impact force along the Z-axis direction, a cross-axis module in the XY direction for absorbing rotational impact torque around the X-axis and rotational impact torque around the Y-axis respectively, and a Z-axis end module in the Z direction for absorbing rotational impact torque around the Z-axis. Furthermore, the Z-axis linear motion module includes a fixed frame unit and a reset frame unit. The reset frame unit is mounted on the fixed frame unit and slidably connected to the fixed frame unit. Between the fixed frame unit and the reset frame unit, there is a linear buffer unit for absorbing the impact force in the Z-axis direction and a Z-axis reset unit for driving the reset frame unit to reset. Furthermore, the fixed frame unit includes two Z-axis linear fixing brackets of type 1 and one Z-axis linear fixing bracket of type 2. The two Z-axis linear fixing brackets of type 1 are arranged opposite each other at both ends of the Z-axis linear fixing bracket of type 2, and the two Z-axis linear fixing brackets of type 1 and one Z-axis linear fixing bracket of type 2 are arranged in a "U" shape. Each Z-axis linear fixing bracket of type 1 and Z-axis linear fixing bracket of type 2 is detachably connected by bolts. A reset plate is installed in the frame formed by the two Z-axis linear fixing brackets of type 1 and Z-axis linear fixing bracket of type 2, and the Z-axis reset unit is installed on the reset plate. Furthermore, the reset frame unit includes a first X-axis fixed bracket, a second X-axis fixed bracket, and a Z-axis reset frame. The first and second X-axis fixed brackets are inserted into the Z-axis reset frame, and are arranged in an "H" shape with the Z-axis reset frame. Both the first and second X-axis fixed brackets are detachably connected to the Z-axis reset frame by bolts. A sliding component is provided on the outer side of each of the first and second X-axis fixed brackets, and the first and second X-axis fixed brackets are slidably connected to the corresponding first Z-axis linear fixed bracket through the sliding component. Furthermore, the linear buffer unit is set between the second Z-axis linear fixing bracket and the Z-axis reset frame. The linear buffer unit includes a linear spring frame, a linear spring, and a linear magnetorheological damper. The tail end of the linear magnetorheological damper passes through the second Z-axis linear fixing bracket and is fixedly connected to the second Z-axis linear fixing bracket by bolts. The top end of the linear magnetorheological damper is connected to a linear spring. The linear spring is limited by the linear spring frame. The top end of the linear spring frame is provided with a connecting flange. The linear spring frame is fixedly connected to the Z-axis reset frame through the connecting flange. Furthermore, the Z-axis reset unit includes a first stroke electric cylinder, which is fixed to the reset plate by a mounting bracket, and the piston end of the first stroke electric cylinder is set towards the Z-axis reset frame. A top block is installed on the piston end of the first stroke electric cylinder, and the first stroke electric cylinder contacts the Z-axis reset frame through the top block. Furthermore, the XY-axis cross-axis module includes a first Y-axis fixed bracket, a second Y-axis fixed bracket, an X-axis axis system structure, and a Y-axis axis system structure. The X-axis axis system structure and the Y-axis axis system structure are arranged perpendicularly at 90° and connected together by a cross-axis bearing seat. The first Y-axis fixed bracket and the second Y-axis fixed bracket are arranged opposite to each other. The Y-axis axis system structure is inserted into the first Y-axis fixed bracket and the second Y-axis fixed bracket, and the X-axis axis system structure is inserted into the first X-axis fixed bracket and the second X-axis fixed bracket. The structure around the X-axis integrates a composite buffer unit for absorbing impact forces around the X-axis and a second reset gear for driving the joint to reset around the X-axis. The Y-axis structure integrates a composite buffer unit for absorbing impact forces in the Y-axis direction and a second reset gear for driving the joint to reset in the Y-axis direction. Furthermore, the reset frame unit is also provided with a rotary reset unit for automatic reset of the joint around the X direction, and the first reset gear in the rotary reset unit is meshed with the second reset gear in the X-axis shaft system structure. Furthermore, the second Y-axis fixed bracket is also equipped with a rotational reset unit for automatic resetting of the joint around the Y direction. The first reset gear in the rotational reset unit is meshed with the second reset gear in the Y-axis shaft system structure. Furthermore, the Z-axis end module includes a Z-axis fixed bracket, which is fixed to the first and second Y-axis fixed brackets by bolts. The Z-axis end module integrates the connection structure of the end effector and a composite buffer unit for absorbing the impact force in the Z-axis direction. The beneficial effects of this application compared to the prior art are: This invention proposes a multi-degree-of-freedom joint device with six-dimensional compliant capture and automatic reset capabilities, particularly suitable for compliant buffering and attitude control of non-cooperative targets in space. This device has the following significant advantages in structural design and functional implementation: The three-module structure proposed in this invention, consisting of a Z-axis linear motion module, an XY-axis cross axis module, and a Z-axis end module, can collaboratively respond to any impact load in six degrees of freedom in space, achieving compliant absorption of multi-axial impact forces and torques. It is particularly suitable for high-speed, non-cooperative target non-structure capture missions, enhancing the overall impact resistance and adaptive capability of the system.
[0007] 2 Each module incorporates a composite buffer mechanism combining a magnetorheological damper with a high-stiffness spring or torsion spring. By utilizing the adaptive adjustment characteristics of magnetorheological materials and the rapid response capability of elastic elements, sensitive buffering under small impacts and efficient unloading under large impacts are achieved, thereby significantly reducing the instantaneous peak stress of key components, ensuring the structural safety of the system and extending its service life.
[0008] 3. This invention has a complete automatic reset function. In the X and Y axes, angle self-feedback and rapid reset are achieved through electric cylinder, reset motor, encoder and gear mechanism. In the Z axis, rigid limit restoration is achieved through electric cylinder drive. This significantly improves task continuity and system recovery efficiency, and meets the engineering requirements of multiple captures and rapid reuse in complex tasks. Attached Figure Description
[0009] Figure 1 A first-view overall structural schematic diagram of the multi-degree-of-freedom compliant joint device provided in this application; Figure 2 Top view of the multi-degree-of-freedom compliant joint device provided in this application; Figure 3 This is a partial schematic diagram of the Z-axis linear motion module in the multi-degree-of-freedom compliant joint device provided in this application; Figure 4 A side view of the Z-axis linear motion module in the multi-degree-of-freedom compliant joint device provided in this application; Figure 5 This is a partial schematic diagram of the XY-axis cross axis module in the multi-degree-of-freedom compliant joint device provided in this application; Figure 6 This is a front view of the cross axis module around the XY direction in the multi-degree-of-freedom compliant joint device provided in this application. Figure 7 This is a schematic diagram of the Z-axis end module in the multi-degree-of-freedom compliant joint device provided in this application. Figure 8 HH-direction cross-sectional view of the Z-direction end module in the multi-degree-of-freedom compliant joint device provided in this application; Figure 9 A schematic diagram of the Z-axis end module in the multi-degree-of-freedom compliant joint device provided in this application; Figure 10 This is a schematic diagram of the principle of the multi-degree-of-freedom compliant joint device provided in this application.
[0010] In the diagram: 1. Linear spring frame; 2. Linear spring; 3. No. 1 stroke electric cylinder; 4. No. 1 X-axis fixed bracket; 5. No. 2 X-axis fixed bracket; 6. Top block; 7. Z-axis reset frame; 8. Pneumatic clamp; 9. Pneumatic clamp guide rail; 10. No. 1 Z-axis linear fixed bracket; 11. No. 2 Z-axis linear fixed bracket; 12. Linear magnetorheological damper; 13. No. 2 stroke electric cylinder; 14. Fixed plate; 15. DC reset motor; 16. Motor fixed bracket; 17. Guide slider; 18. Guide slide rail; 19. No. 1 reset gear; 20. Rotary magnetorheological damper; 21. No. 1 Y-axis fixed bracket. Fixed bracket, 22 No. 2 reset gear, 23 encoder, 24 No. 2 fixed bracket around the Y axis, 25 cross shaft bearing seat, 26 flange optical shaft fixer, 27 reset support plate, 28 left-hand torsion spring, 29 right-hand torsion spring, 30 fixed bracket around the Z axis damper, 31 fixed bracket around the Z axis, 32 slewing bearing, 33 Z-direction extension shaft, 34 end effector connecting plate, 35 bidirectional torsion spring, 36 torsion spring fixing bracket, 37 No. 1 broken shaft, 38 No. 2 broken shaft, 39 through shaft around the X direction, 40 air foot, 41 No. 1 air foot bracket and 42 No. 2 air foot bracket. Detailed Implementation
[0011] Specific implementation method one: Combining Figures 1 to 10 This embodiment describes a multi-degree-of-freedom joint device with six-dimensional compliant capture and reset capability. The multi-degree-of-freedom joint device includes a Z-axis linear motion module for absorbing impact force along the Z-axis direction. The Z-axis linear motion module is equipped with a cross-axis module in the XY direction for absorbing rotational impact torque around the X-axis and rotational impact torque around the Y-axis, respectively. The cross-axis module in the XY direction is equipped with a Z-axis end module for absorbing rotational impact torque around the Z-axis. The Z-axis linear motion module includes a fixed frame unit and a reset frame unit. The reset frame unit is mounted on the fixed frame unit and slidably connected to the fixed frame unit. Between the fixed frame unit and the reset frame unit, there is a linear buffer unit for absorbing the impact force in the Z-axis direction and a Z-axis reset unit for driving the reset frame unit to reset. The XY-axis cross-axis module includes a first Y-axis fixed bracket 21, a second Y-axis fixed bracket 24, an X-axis axis system structure, and a Y-axis axis system structure. The X-axis axis system structure and the Y-axis axis system structure are arranged perpendicularly at 90° and connected together by a cross-axis bearing seat 25. The first Y-axis fixed bracket 21 and the second Y-axis fixed bracket 24 are arranged opposite to each other. The Y-axis axis system structure is inserted into the first Y-axis fixed bracket 21 and the second Y-axis fixed bracket 24, and the X-axis axis system structure is inserted into the first X-axis fixed bracket 4 and the second X-axis fixed bracket 5. The structure around the X-axis integrates a composite buffer unit for absorbing impact forces around the X-axis and a second reset gear 22 for driving the joint to reset around the X-axis. The Y-axis structure integrates a composite buffer unit for absorbing impact forces in the Y-axis direction and a second reset gear 22 for driving the joint to reset in the Y-axis direction. The Z-axis end module includes a Z-axis fixed bracket 31, which is fixed to a first Y-axis fixed bracket 21 and a second Y-axis fixed bracket 24 by bolts. The Z-axis end module integrates the connection structure of the end effector and a composite buffer unit for absorbing the impact force in the Z-axis direction.
[0012] This embodiment provides a multi-degree-of-freedom joint device with six-dimensional compliant capture and reset capabilities. The complete structure comprises a Z-axis linear motion module, an XY-axis cross-axis module, and a Z-axis end-effector module. The Z-axis linear motion module absorbs impact forces along the Z-axis; the XY-axis cross-axis module absorbs torque impacts around the X and Y axes, respectively; and the Z-axis end-effector module absorbs rotational impact torques around the Z-axis. For linear impacts along the X and Y axes, the Z-axis linear motion module and the XY-axis cross-axis module work together to absorb them. Impacts in the X-axis direction are buffered by rotational clearance around the Y-axis and linear clearance in the Z-axis direction, while impacts in the Y-axis direction are buffered by rotational clearance around the X-axis and linear clearance in the Z-axis direction, thus achieving a flexible buffering response in multiple degrees of freedom. The fixed frame unit in the Z-axis linear motion module includes two first Z-axis linear fixed brackets 10 and one second Z-axis linear fixed bracket 11. The two first Z-axis linear fixed brackets 10 are arranged opposite each other at both ends of the second Z-axis linear fixed bracket 11, and the two first Z-axis linear fixed brackets 10 and the second Z-axis linear fixed bracket 11 are arranged in a "U" shape. Each first Z-axis linear fixed bracket 10 and the second Z-axis linear fixed bracket 11 are detachably connected by bolts. A reset plate 27 is installed in the frame formed by the two first Z-axis linear fixed brackets 10 and the second Z-axis linear fixed bracket 11. The Z-axis reset unit is installed on the reset plate 27. The reset frame unit includes a first X-axis fixed bracket 4, a second X-axis fixed bracket 5, and a Z-axis reset frame 7. The first X-axis fixed bracket 4 and the second X-axis fixed bracket 5 are inserted into the Z-axis reset frame 7, and the first X-axis fixed bracket 4 and the second X-axis fixed bracket 5 are arranged in an "H" shape with the Z-axis reset frame 7. The first X-axis fixed bracket 4 and the second X-axis fixed bracket 5 are detachably connected to the Z-axis reset frame 7 by bolts. A sliding component is provided on the outer side of the first X-axis fixed bracket 4 and the second X-axis fixed bracket 5. The first X-axis fixed bracket 4 and the second X-axis fixed bracket 5 are slidably connected to the corresponding first Z-axis linear fixed bracket 10 through the sliding component.
[0013] The sliding assembly between the reset frame unit and the fixed frame unit consists of a pneumatic clamp 8 and a pneumatic clamp guide rail 9. Pneumatic clamp guide rails 9 are respectively mounted on the outside of the first X-axis fixed bracket 4 and the second X-axis fixed bracket 5, and the pneumatic clamp 8 is slidably installed on them. The pneumatic clamp 8 is fixed on the first Z-axis linear fixed bracket 10 by bolts. A linear buffer unit is set between the fixed frame unit and the reset frame unit. The linear buffer unit includes a linear spring frame 1, a linear spring 2, and a linear magnetorheological damper 12. The tail end of the linear magnetorheological damper 12 passes through the second Z-axis linear fixed bracket 11 and is fixedly connected to the second Z-axis linear fixed bracket 11 by bolts. The linear magnetorheological damper 12 is used to provide flexible guidance and buffering function. The top end of the linear magnetorheological damper 12 is connected to the linear spring 2. The linear spring 2 is limited by the linear spring frame 1. The top end of the linear spring frame 1 is provided with a connecting flange. The linear spring frame 1 is fixedly connected to the Z-axis reset frame 7 by the connecting flange. The linear spring 2 is used to achieve cooperation with the Z-axis reset fixed bracket 7 and elastic buffering. The X-axis axial system includes an X-axis through shaft 39, which is inserted into a cross shaft bearing seat 25 and limited by two flange optical shaft retainers 26. An encoder 23 is located at one end of the X-axis through shaft 39 near the first X-axis fixing bracket 4. The encoder 23 is bolted to the first X-axis fixing bracket 4 and fixed to the shaft end of the X-axis through shaft 39 by a hoop. A second reset gear 22 is located on the side of the encoder 23 near the cross shaft bearing seat 25, and the second reset gear 22 is fitted onto the X-axis through shaft 39. This second reset gear 22 interacts with the joint in the X-axis direction. The automatic reset rotary reset unit is set accordingly. The other end of the through shaft 39 around the X direction is connected to a rotary magnetorheological damper 20 through a set screw. The rotary magnetorheological damper 20 is fixed to the second X-axis fixed bracket 5 by bolts. A right-handed torsion spring 29 and a left-handed torsion spring 28 are also installed at both ends of the through shaft 39 around the X direction. After straightening one end of each torsion spring, it is inserted into the small hole in the first X-axis fixed bracket 4 or the second X-axis fixed bracket 5 and fixed to the first X-axis fixed bracket 4 or the second X-axis fixed bracket 5 by bolts. The other end of each torsion spring is fixed to the through shaft 39 around the X direction by a hoop. The composition of the X-axis shaft system is almost identical to that of the Y-axis shaft system. The difference is that, in order to prevent the two shaft systems from interfering with each other during operation, the Y-axis through shaft in the Y-axis shaft system is replaced by broken shaft 37 and broken shaft 38. The Y-axis axial system includes a first broken shaft 37 and a second broken shaft 38, which are coaxially arranged opposite each other on both sides of the X-axis through shaft 39. The first broken shaft 37 and the second broken shaft 38 are respectively limited to the cross shaft bearing seat 25 by a flange optical shaft retainer 26. From the cross shaft bearing seat 25 outwards, the first broken shaft 37 is sequentially fitted with a second reset gear 22, a right-hand torsion spring 29, and an encoder 23. One end of the right-hand torsion spring 29, after being straightened, is inserted into a small hole in the second Y-axis fixed bracket 24 and fixed to the second Y-axis fixed bracket 24 by bolts. The other end of the right-hand torsion spring 29 is fixed to a clamp. On the first broken shaft 37, the encoder 23 is fixed to the second Y-axis fixed bracket 24 by bolts and fixed to the shaft end of the first broken shaft 37 by a hoop. The second broken shaft 38 is fitted with a left-hand torsion spring 28 and a rotary magnetorheological damper 20 in sequence from the cross shaft bearing seat 25 outwards. One end of the left-hand torsion spring 28 is straightened and inserted into the small hole in the first Y-axis fixed bracket 21 and fixed to the first Y-axis fixed bracket 21 by bolts. The other end of the left-hand torsion spring 28 is fixed to the second broken shaft 38 by a hoop. The rotary magnetorheological damper 20 is fixed to the first Y-axis fixed bracket 21 by bolts and connected to the shaft end of the second broken shaft 38 by a set screw. The Z-axis end module includes a Z-axis fixed bracket 31, which is bolted to a first Y-axis fixed bracket 21 and a second Y-axis fixed bracket 24. Below the Z-axis fixed bracket 31 is a Z-axis damper fixed bracket 30 for mounting a rotating magnetorheological damper 20 to achieve damping control in the Z-direction. A rotary bearing 32 is connected above the Z-axis fixed bracket 31. The outer ring of the rotary bearing 32 is bolted to a fixed structure, and the inner ring is bolted to an end actuator connecting plate 34. The end actuator connecting plate 34 is connected to a Z-axis extension shaft 33 via a set screw. The other end of the Z-axis extension shaft 33 is also bolted to the rotating magnetorheological damper 20. A bidirectional torsion spring 35 is installed inside this module. One end of the bidirectional torsion spring 35 is fixed to the Z-axis extension shaft 33 via a hoop, and the other end is fixed to a torsion spring fixing frame 36. The torsion spring fixing frame 36 is bolted to the Z-axis fixed bracket 31, thus forming a three-dimensional compliant torsional structure. The multi-degree-of-freedom joint device with six-dimensional compliant capture and reset capability provided in this embodiment also includes a support structure for stabilizing the entire system. The support structure consists of three air feet 40. Two first-order air foot brackets 41 and one second-order air foot bracket 42 are provided at the bottom of the reset plate 27. The two first-order air foot brackets 41 and one second-order air foot bracket 42 are arranged in an isosceles triangle. Each air foot bracket is equipped with a corresponding air foot 40, and the three air feet 40 are located on the same plane.
[0014] Specific Implementation Method Two: Combining Figures 1 to 10 This embodiment differs from the first specific embodiment in that the reset frame unit is further provided with a rotary reset unit for automatic reset of the joint around the X direction, and the first reset gear 19 in the rotary reset unit is meshed with the second reset gear 22 in the X-axis shaft system structure. The second Y-axis fixed bracket 24 is also equipped with a rotational reset unit for automatic joint reset around the Y direction. The first reset gear 19 in the rotational reset unit is meshed with the second reset gear 22 in the Y-axis axis system. Other components and connection methods are the same as in specific embodiment one.
[0015] In this embodiment, the rotational reset unit for automatic reset of the joint around the Y direction and automatic reset of the joint around the X direction have the same structure. They are both composed of a second stroke electric cylinder 13, a DC reset motor 15, a motor fixing bracket 16 and a first reset gear 19. The second stroke electric cylinder 13 is a 10mm working stroke electric cylinder. In the rotary reset unit for automatic joint reset around the X-axis, the second stroke electric cylinder 13 is fixed to the inner side of the first X-axis fixed bracket 4 via a mounting bracket. The piston end of the second stroke electric cylinder 13 is connected to the motor fixed bracket 16 via a fixing plate 14. The second stroke electric cylinder 13 serves as a power source to drive the motor fixed bracket 16 to move on the first X-axis fixed bracket 4. To prevent interference during the movement of the motor fixed bracket 16, a guide through hole is machined on the first X-axis fixed bracket 4 to cooperate with the DC reset motor 15. Guide slide rails 18 are provided on both sides of the guide through hole. The guide rail 18 is fixed inside the first X-axis fixed bracket 4. The guide rail 18 is equipped with a guide slider 17, which is installed on the back side of the motor fixed bracket 16. The motor fixed bracket 16 is equipped with a DC reset motor 15, and the power output shaft of the DC reset motor 15 is set towards the second X-axis fixed bracket 5. The power output shaft of the DC reset motor 15 is fitted with a first reset gear 19. The DC reset motor 15 drives the first reset gear 19 to mesh with the corresponding second reset gear 22 in the X-axis axis system structure, thereby realizing the reset of the joint in the X-direction. In the rotary reset unit for automatic joint reset around the Y-axis, the second stroke electric cylinder 13 is fixed to the inner side of the second Y-axis fixed bracket 24 via a mounting bracket. The piston end of the second stroke electric cylinder 13 is connected to the motor fixed bracket 16 via a fixing plate 14. The second stroke electric cylinder 13 acts as a power source to drive the motor fixed bracket 16 to move on the second Y-axis fixed bracket 24. To prevent interference during the movement of the motor fixed bracket 16, a guide through hole is machined on the second Y-axis fixed bracket 24 to cooperate with the DC reset motor 15. Guide rails 18 are provided on both sides of the guide through hole to guide... The slide rail 18 is fixed inside the first X-axis fixed bracket 4. The guide slide rail 18 is equipped with a guide slider 17, which is installed on the back side of the motor fixed bracket 16. The motor fixed bracket 16 is equipped with a DC reset motor 15, and the power output shaft of the DC reset motor 15 is set towards the second Y-axis fixed bracket 21. The power output shaft of the DC reset motor 15 is fitted with a first reset gear 19. The DC reset motor 15 drives the first reset gear 19 to mesh with the corresponding second reset gear 22 in the Y-axis axis structure, thereby realizing the reset of the joint in the Y-direction.
[0016] Specific implementation method three: Combining Figures 1 to 10 This embodiment differs from Specific Embodiment Two in that the Z-axis reset unit includes a first-stroke electric cylinder 3, which is fixed to the reset plate by a mounting bracket. The piston end of the first-stroke electric cylinder 3 faces the Z-axis reset frame 7, and a top block 6 is mounted on the piston end of the first-stroke electric cylinder 3. The first-stroke electric cylinder 3 contacts the Z-axis reset frame 7 through the top block 6. Other components and connections are the same as in Specific Embodiment Two.
[0017] In this embodiment, the first stroke electric cylinder 3 is a 50mm working stroke electric cylinder. During operation, the first stroke electric cylinder 3 pushes the Z-axis reset frame 7 through the top block 6 to reset.
[0018] The present invention has been disclosed above with preferred embodiments, but it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed structure and technical content to create equivalent embodiments without departing from the scope of the present invention. However, any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.
[0019] Working principle When the target rapidly approaches and comes into contact with the end effector connecting plate 34, it is assumed that the target applies a typical six-dimensional impact load, which can be decomposed into a positive compressive force along the Z-axis, such as the target's vertical thrust, and a disturbance torque around the Y-axis, such as the target's deflection impact. In this type of impact scenario, the end effector connecting plate 34 is first affected by the applied torque, causing the first Y-axis fixed bracket 21 and the second Y-axis fixed bracket 24 connected to it to rotate around the Y-axis. Since the second broken shaft 38 used in the Y-direction is kept fixed to the structure through the flange optical shaft retainer 26, the rotational motion is effectively transmitted to the left-hand torsion spring 28 and the rotating magnetorheological damper 20. Among them, the left-hand torsion spring 28, with its high stiffness characteristics, quickly provides a reverse torque in the initial stage of the impact, playing a major role in compliance buffering; the rotating magnetorheological damper 20 responds synchronously, but its force is smaller, effectively reducing its instantaneous load.
[0020] Simultaneously, the impact process is typically accompanied by a compressive component along the Z-axis. For example, if the target exhibits a slight diving tendency during impact, a downward compressive force is generated on the device while applying torque around the Y-axis. This compressive force is transmitted along the Z-axis to the Z-axis reset bracket 7, further compressing the linear spring 2 and activating the linear magnetorheological damper 12. The linear spring 2 provides the primary deformation response, while the linear magnetorheological damper 12 provides auxiliary buffering damping, ensuring that structural damage from rigid collisions is avoided during the initial stress phase.
[0021] By coordinating the operation of two sets of compliant buffer structures in the torsional and linear directions, this invention can dynamically achieve compliant capture under typical composite impact loads of "Z-axis compression + Y-axis torque," while minimizing the instantaneous stress concentration problem of the magnetorheological damper while ensuring system response performance. The device also has an automatic reset capability: rotation around the X and Y axes is recorded in real time by an absolute encoder. When the system needs to reset, the second stroke electric cylinder 13 is activated, pushing the first reset gear 19 to mesh with the second reset gear 22. The encoder 23 feeds back the current angle information to the DC reset motor 15, which drives the first reset gear 19 to rotate, thereby driving the second reset gear 22, which is fixed to the shaft, to rotate, completing a precise reset around the X or Y axis.
[0022] For Z-axis resetting, the Z-axis resetting bracket 7 is pushed beyond the stroke range of the linear magnetorheological damper 12 by an electric cylinder, thereby achieving structural positioning and restoration with the help of rigid boundaries. Pneumatic clamps 8 are provided on both sides of the Z-axis linear motion module, which can clamp and limit the module during the capture process, further improving the stability of the capture posture and the overall safety of the system operation.
Claims
1. A multi-degree-of-freedom joint device with six-dimensional compliant capture and reset capability, characterized in that: The multi-degree-of-freedom joint device includes a Z-axis linear motion module for absorbing impact forces along the Z-axis direction. The Z-axis linear motion module is equipped with XY-axis cross-axis modules for absorbing rotational impact torques around the X-axis and Y-axis, respectively. The XY-axis cross-axis modules are equipped with Z-axis end modules for absorbing rotational impact torques around the Z-axis.
2. The multi-degree-of-freedom joint device with six-dimensional compliant capture and reset capability according to claim 1, characterized in that: The Z-axis linear motion module includes a fixed frame unit and a reset frame unit. The reset frame unit is mounted on the fixed frame unit and slidably connected to the fixed frame unit. Between the fixed frame unit and the reset frame unit, there is a linear buffer unit for absorbing impact forces in the Z-axis direction and a Z-axis reset unit for driving the reset frame unit to reset.
3. A multi-degree-of-freedom joint device with six-dimensional compliant capture and reset capability according to claim 2, characterized in that: The fixed frame unit includes two Z-axis linear fixing brackets (10) and one Z-axis linear fixing bracket (11). The two Z-axis linear fixing brackets (10) are arranged opposite each other at both ends of the Z-axis linear fixing bracket (11), and the two Z-axis linear fixing brackets (10) and the Z-axis linear fixing bracket (11) are arranged in a "U" shape. Each Z-axis linear fixing bracket (10) and the Z-axis linear fixing bracket (11) are detachably connected by bolts. A reset plate (27) is installed in the frame formed by the two Z-axis linear fixing brackets (10) and the Z-axis linear fixing bracket (11). The Z-axis reset unit is installed on the reset plate (27).
4. A multi-degree-of-freedom joint device with six-dimensional compliant capture and reset capability according to claim 3, characterized in that: The reset frame unit includes a first X-axis fixed bracket (4), a second X-axis fixed bracket (5), and a Z-axis reset frame (7). The first X-axis fixed bracket (4) and the second X-axis fixed bracket (5) are inserted into the Z-axis reset frame (7), and the first X-axis fixed bracket (4) and the second X-axis fixed bracket (5) are arranged in an "H" shape with the Z-axis reset frame (7). The first X-axis fixed bracket (4) and the second X-axis fixed bracket (5) are detachably connected to the Z-axis reset frame (7) by bolts. A sliding component is provided on the outside of the first X-axis fixed bracket (4) and the second X-axis fixed bracket (5). The first X-axis fixed bracket (4) and the second X-axis fixed bracket (5) are slidably connected to the corresponding first Z-axis linear fixed bracket (10) through the sliding component.
5. A multi-degree-of-freedom joint device with six-dimensional compliant capture and reset capability according to claim 4, characterized in that: The linear buffer unit is set between the second Z-axis linear fixed bracket (11) and the Z-axis reset frame (7). The linear buffer unit includes a linear spring frame (1), a linear spring (2) and a linear magnetorheological damper (12). The tail end of the linear magnetorheological damper (12) passes through the second Z-axis linear fixed bracket (11) and is fixedly connected to the second Z-axis linear fixed bracket (11) by bolts. The top end of the linear magnetorheological damper (12) is connected to the linear spring (2). The linear spring (2) is limited by the linear spring frame (1). The top end of the linear spring frame (1) is provided with a connecting flange. The linear spring frame (1) is fixedly connected to the Z-axis reset frame (7) by the connecting flange.
6. A multi-degree-of-freedom joint device with six-dimensional compliant capture and reset capability according to claim 5, characterized in that: The Z-axis reset unit includes a first stroke electric cylinder (3), which is fixed on the reset plate by a mounting bracket. The piston end of the first stroke electric cylinder (3) faces the Z-axis reset frame (7). A top block (6) is installed on the piston end of the first stroke electric cylinder (3), and the first stroke electric cylinder (3) contacts the Z-axis reset frame (7) through the top block (6).
7. A multi-degree-of-freedom joint device with six-dimensional compliant capture and reset capability according to claim 6, characterized in that: The XY-axis cross axis module includes a first Y-axis fixed bracket (21), a second Y-axis fixed bracket (24), an X-axis axis system structure, and a Y-axis axis system structure. The X-axis axis system structure and the Y-axis axis system structure are arranged perpendicularly at 90° and connected together by a cross axis bearing seat (25). The first Y-axis fixed bracket (21) and the second Y-axis fixed bracket (24) are arranged opposite to each other. The Y-axis axis system structure is inserted into the first Y-axis fixed bracket (21) and the second Y-axis fixed bracket (24). The X-axis axis system structure is inserted into the first X-axis fixed bracket (4) and the second X-axis fixed bracket (5). The structure around the X-axis integrates a composite buffer unit for absorbing impact forces around the X-axis and a second reset gear (22) for driving the joint to reset around the X-axis. The Y-axis structure integrates a composite buffer unit for absorbing impact forces in the Y-axis direction and a second reset gear (22) for driving the joint to reset in the Y-axis direction.
8. A multi-degree-of-freedom joint device with six-dimensional compliant capture and reset capability according to claim 7, characterized in that: The reset frame unit is also provided with a rotary reset unit for automatic reset of the joint around the X direction. The first reset gear (19) in the rotary reset unit is meshed with the second reset gear (22) in the X-axis shaft system.
9. A multi-degree-of-freedom joint device with six-dimensional compliant capture and reset capability according to claim 8, characterized in that: The second Y-axis fixed bracket (24) is also equipped with a rotation reset unit for automatic resetting of the joint around the Y direction. The first reset gear (19) in the rotation reset unit is meshed with the second reset gear (22) in the Y-axis axis system.
10. A multi-degree-of-freedom joint device with six-dimensional compliant capture and reset capability according to claim 9, characterized in that: The Z-axis end module includes a Z-axis fixed bracket (31), which is fixed to the first Y-axis fixed bracket (21) and the second Y-axis fixed bracket (24) by bolts. The Z-axis end module integrates the connection structure of the end effector and the composite buffer unit for absorbing the impact force in the Z-axis direction.