A three-degree-of-freedom soft docking joint for unloading spatial six-dimensional impulse

Abstract

The present application relates to the technical field of space robot, in particular to a kind of three degrees of freedom soft docking joint, including transmission mechanism, damping buffer component and sensing component.The transmission mechanism includes clutch, cross shaft structure, Z-axis rotating shell, Y-axis rotating shell etc.;Damping buffer component includes rotary magneto-rheological damper and torsional spring mechanism etc.;Sensing component includes encoder etc.The soft docking joint mainly utilizes damping buffer component to control the flexibility of docking mechanism, according to operation task to realize space six-dimensional momentum unloading, to realize the soft docking of space operation.

Description

Technical Field

[0001] This invention relates to the field of space robot technology, specifically a three-degree-of-freedom soft docking joint for unloading six-dimensional impulse in space. Background Technology

[0002] With the rapid development of space activities worldwide, the number of new spacecraft launched into orbit is increasing year by year, while older, defunct spacecraft continue to occupy limited orbital resources, thus eroding these precious resources. Utilizing space robots for on-orbit docking and capture technology to clean up space debris or maintain defunct satellites is of great significance for the sustainable use of space orbital resources. During rendezvous and docking in space, two spacecraft will come into contact and collide, resulting in asymmetrical momentum transfer. To avoid unnecessary damage and deformation during the collision, reduce the risk of spacecraft runaway, and ensure spacecraft safety, a damping buffer system needs to be designed on the docking mechanism to achieve a soft docking with momentum unloading capabilities.

[0003] Current space docking technologies mainly involve cone-shaped docking, electromagnetic docking, net capture, and rigid robotic arm capture, with docking primarily achieved through flexible ropes or end effectors. Regarding constraints, high precision is required for relative attitude measurement, tracking, maintaining, and instantaneous attitude disturbance between the two spacecraft, making implementation extremely challenging. Summary of the Invention

[0004] To address the challenges of energy impact during space robot docking operations and the energy step transfer between two spacecraft under various complex space conditions, this invention designs a three-degree-of-freedom soft docking joint for unloading six-dimensional momentum in space. This joint has three degrees of freedom in a Cartesian coordinate system, rotating around the X, Y, and Z axes without interference between them. The revolute joints around the Y and Z axes are offset relative to the X-axis. A damping buffer component is incorporated into the mechanism, enabling six-dimensional momentum unloading and thus achieving smooth soft docking during spacecraft docking. This reduces the risks associated with hard docking in current space operations, expanding the applicability and reliability of space robot operations. A clutch is incorporated to control the relative motion of the revolute joints. When the mechanism is not performing docking tasks, the joints are locked, making the mechanism rigid; when performing docking tasks, the joints are released, making the mechanism flexible.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] A three-degree-of-freedom soft docking joint for unloading six-dimensional impulse in space mainly includes a transmission mechanism, a damping buffer assembly, and a sensing assembly.

[0007] The transmission mechanism includes a fixed plate (101), a Y-axis rotating housing (102), a Z-axis rotating housing (108), a bracket one (103), a bracket two (105), a bracket three (106), a bracket four (107), a bracket five (110), a bracket six (111), a bracket seven (112), a bracket eight (203), a bracket nine (306), a bracket ten (313), a coupling (307), a rotating spindle Z (213), a rotating spindle Y (214), a rotating spindle X (315), a spindle X fixed fastener (314), a deep groove ball bearing one (301), a deep groove ball bearing two (303), a sleeve (302), a clutch X (310), a clutch Y (205), and a clutch Z (209). The Y-axis rotating housing (102) and the Z-axis rotating housing (108) offset the cross shaft (202) relative to the X-axis to achieve the end of the mechanism... The linear impulse received in the X-axis direction is buffered and unloaded. The end of the mechanism is an external capture mechanism connected to the fixed plate (101). The damping buffer assembly includes a torsion spring seat X (311), a torsion spring seat Y (104), a torsion spring seat Z (109), a torsion spring fastener X (304), a torsion spring fastener Y (208), a torsion spring fastener Z (212), a torsion spring X (305), a torsion spring Y (206), a torsion spring Z (210), a rotary magnetorheological damper X (308), a rotary magnetorheological damper Y (201), a rotary magnetorheological damper Z (204), a damping shaft X (309), and a cross shaft (202). The sensing assembly consists of an encoder X (312), an encoder Y (207), and an encoder Z (211), and is mainly used for measuring angular displacement and angular velocity when rotating around the X-axis, Y-axis, and Z-axis.

[0008] The rotary magnetorheological damper Y (201) is mounted on bracket five (110), and the rotary magnetorheological damper Z (204) is mounted on bracket eight (203). The rotation shafts of the rotary magnetorheological dampers Y (201) and Z are served by a cross shaft (202). The rotors of clutches Y (205) and Z (209) are connected to the cross shaft (202) via keys. The stator of clutch Y (205) is connected to bracket two (105), and the stator of clutch Z (209) is connected to bracket three (106). The encoder Y (207) is connected to the torsion spring seat Y. (104) is connected to bracket two (105), encoder Z (211) is connected to bracket four (107) through torsion spring seat Z (109), and the rotation axis of encoder Y (207) and encoder Z (211) is served by cross shaft (202); the torsion spring Y (206) is connected to cross shaft (202) at one end through torsion spring fastener Y (208) and to torsion spring seat Y (104) at the other end; the torsion spring Z (210) is connected to cross shaft (202) at one end through torsion spring fastener Z (212) and to torsion spring seat Z (109) at the other end.

[0009] The rotary magnetorheological damper X (308) is connected to bracket six (111), and its rotation axis is the damping shaft X (309); the rotor of clutch X (310) is connected to the rotating main shaft X (315) via a key, and the stator of clutch X (310) is connected to bracket nine (306). Bracket nine (306) is connected to bracket six (111) via symmetrically arranged bracket seven (112); encoder X (312) is connected to bracket nine via torsion spring seat X (311). (306) Its motion axis is the rotating spindle X (315); in addition, the rotating spindle X (315) is connected to the rotating inner shell through the rotating spindle X fixed connector (314) to achieve synchronous rotation; one end of the torsion spring X (305) is connected to the rotating spindle X (315) through the torsion spring fixed connector X (304), and the other end is connected to the torsion spring seat X (311); the damping shaft X (309) is connected to the rotating spindle X (315) through the coupling (307) to achieve transmission.

[0010] The Y-axis rotating housing (102) is connected to the bracket (313); a deep groove ball bearing (301) and a deep groove ball bearing (303) are installed between the fixing plate (101) and the Y-axis rotating housing (102) to achieve relative rotation.

[0011] The rotary magnetorheological damper X (308) and torsion spring X (305) form an X-axis rotary damping buffer assembly; the rotary magnetorheological damper Y (201) and torsion spring Y (206) form a Y-axis rotary damping buffer assembly; the rotary magnetorheological damper Z (204) and torsion spring Z (210) form a Z-axis rotary damping buffer assembly.

[0012] Compared with the prior art, the present invention has the following characteristics:

[0013] 1. This mechanism is designed by offsetting the Y-axis and Z-axis rotary kinematic pairs relative to the X-axis. It only requires three degrees of freedom to rotate around the X-axis, Y-axis and Z-axis to achieve buffering and unloading of six-dimensional spatial impulses. Moreover, the three degrees of freedom do not interfere with each other, thus achieving motion decoupling. Under the control of the electromagnetic clutch, the mechanism can exhibit both rigid and flexible states.

[0014] 2. This mechanism is designed with three sets of rotational damping buffers to unload momentum impact during docking. The linear momentum along the X and Y axes is converted into momentum about the Z axis and unloaded by the Z-axis rotational damping buffer; the linear momentum along the Z axis is converted into momentum about the Y axis and unloaded by the Y-axis rotational damping buffer; the momentum about the X, Y, and Z axes is unloaded by the three sets of rotational damping buffers about the X, Y, and Z axes, respectively. Therefore, this mechanism can achieve six-dimensional momentum unloading in space, thus achieving smooth soft contact during spacecraft docking.

[0015] 3. This mechanism employs a magnetorheological damper with a flexible and controllable damping coefficient, enabling semi-active control of the mechanism. The magnetorheological damper has excellent characteristics such as low energy consumption, simple structure, continuously and reversibly adjustable damping force with a large adjustable range, fast response, good temperature stability, and compatibility with microcomputer control. Therefore, it can be applied to space soft docking mechanisms to reduce impact vibration loads, unload momentum, and absorb collision kinetic energy. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the overall appearance structure of a specific embodiment of the present invention;

[0017] Figure 2 This is a partial external structural diagram of a specific embodiment of the present invention;

[0018] Figure 3 This is a partial internal structure diagram of a specific embodiment of the present invention.

[0019] The labels in the attached diagram are explained as follows:

[0020] Fixed plate (101), Y-axis rotating housing (102), bracket one (103), torsion spring seat Y (104), bracket two (105), bracket three (106), bracket four (107), Z-axis rotating housing (108), torsion spring seat Z (109), bracket five (110), bracket six (111), bracket seven (112), rotary magnetorheological damper Y (201), cross shaft (202), bracket eight (203), rotary magnetorheological damper Z (204), clutch Y (205), torsion spring Y (206), encoder Y (207), torsion spring fastener Y (208), clutch Z (205). 9), Torsion spring Z (210), Encoder Z (211), Torsion spring fastener Z (212), Rotary spindle Z (213), Rotary spindle Y (214), Deep groove ball bearing I (301), Sleeve (302), Deep groove ball bearing II (303), Torsion spring fastener X (304), Torsion spring X (305), Bracket IX (306), Coupling (307), Rotary magnetorheological damper X (308), Damping shaft X (309), Clutch X (310), Torsion spring seat X (311), Encoder X (312), Bracket X (313), Spindle X fastener (314), Rotary spindle X (315). Detailed Implementation Plan

[0021] The following is in conjunction with the appendix Figures 1-3 Further explanation of the present invention:

[0022] The present invention comprises three parts: a transmission mechanism, a damping buffer assembly, and a sensing assembly.

[0023] The transmission mechanism includes a fixed plate (101), a Y-axis rotating housing (102), a Z-axis rotating housing (108), a bracket 1 (103), a bracket 2 (105), a bracket 3 (106), a bracket 4 (107), a bracket 5 (110), a bracket 6 (111), a bracket 7 (112), a bracket 8 (203), a bracket 9 (306), a bracket 10 (313), a coupling (307), a rotating spindle Z (213), a rotating spindle Y (214), a rotating spindle X (315), a spindle X fixed fastener (314), a deep groove ball bearing 1 (301), a deep groove ball bearing 2 (303), a sleeve (302), a clutch X (310), a clutch Y (205), and a clutch Z (209). The damping buffer assembly includes a torsion spring seat X (311), a torsion spring seat Y (104), a torsion spring seat Z (109), a torsion spring fastener X (304), a torsion spring fastener Y (208), a torsion spring fastener Z (212), a torsion spring X (305), a torsion spring Y (206), a torsion spring Z (210), a rotary magnetorheological damper X (308), a rotary magnetorheological damper Y (201), a rotary magnetorheological damper Z (204), a damping shaft X (309), and a cross shaft (202); the sensing assembly includes an encoder X (312), an encoder Y (207), and an encoder Z (211), used for measuring angular displacement and angular velocity when rotating around the X-axis, Y-axis, and Z-axis.

[0024] The rotary magnetorheological damper Y (201) is mounted on bracket five (110), and the rotary magnetorheological damper Z (204) is mounted on bracket eight (203). The rotation shafts of the rotary magnetorheological dampers Y (201) and Z (204) are served by a cross shaft (202). The rotors of clutches Y (205) and Z (209) are connected to the cross shaft (202) via keys. The stator of clutch Y (205) is connected to bracket two (105), and the stator of clutch Z (209) is connected to bracket three (106). The encoder Y (207) is connected via... The torsion spring seat Y (104) is connected to the bracket two (105), and the encoder Z (211) is connected to the bracket four (107) through the torsion spring seat Z (109). The rotation axis of the encoder Y (207) and the encoder Z (211) is served by the cross shaft. The torsion spring Y (206) is connected to the cross shaft (202) at one end through the torsion spring fastener Y (208) and to the torsion spring seat Y (104) at the other end. The torsion spring Z (210) is connected to the cross shaft (202) at one end through the torsion spring fastener Z (212) and to the torsion spring seat Z (109) at the other end.

[0025] The rotary magnetorheological damper X (308) is connected to bracket six (111), and its rotation axis is the damping shaft X (309); the rotor of clutch X (310) is connected to the rotating main shaft X (315) via a key, and the stator of clutch X (310) is connected to bracket nine (306). Bracket nine (306) is connected to bracket six (111) via symmetrically arranged bracket seven (112); encoder X (312) is connected to bracket nine (111) via torsion spring seat X (311). 306) is connected, and its shaft is the rotating spindle X (315); in addition, the rotating spindle X (315) is connected to the rotating inner shell through the rotating spindle X fixed connector (314) to achieve synchronous rotation; one end of the torsion spring X (305) is connected to the rotating spindle X (315) through the torsion spring fixed connector X (304), and the other end is connected to the torsion spring seat X (311); the damping shaft X (309) is connected to the rotating spindle X (315) through the coupling (307) to achieve transmission.

[0026] The Y-axis rotating housing (102) is connected to the bracket (313); a deep groove ball bearing (301) and a deep groove ball bearing (303) are installed between the fixing plate (101) and the Y-axis rotating housing (102) to achieve relative rotation.

[0027] The rotary magnetorheological damper X (308) and torsion spring X (305) form an X-axis rotary damping buffer assembly; the rotary magnetorheological damper Y (201) and torsion spring Y (206) form a Y-axis rotary damping buffer assembly; the rotary magnetorheological damper Z (204) and torsion spring Z (210) form a Z-axis rotary damping buffer assembly.

[0028] When not performing docking tasks, clutches X (310), Y (205), and Z (209) are all in an energized and locked state. The cross shaft (202) remains relatively fixed to brackets two (105), three (106), five (110), and eight (203). The Y-axis rotating housing (102) and the Z-axis rotating housing (108) remain relatively fixed, and the entire mechanism is in a rigid state.

[0029] When performing the docking task, clutches X (310), Y (205), and Z (209) are all de-energized and disconnected. The cross shaft (202) moves relative to supports two (105), three (106), five (110), and eight (203), and the Y-axis rotating outer shell (102) moves relative to the Z-axis rotating outer shell (108). The entire mechanism exhibits a flexible state. The mechanism contains three sets of damping buffer components that can unload momentum during the docking process. Linear momentum along the X and Y axes is converted into angular momentum around the Z-axis and unloaded by the Z-axis rotational damping buffer component. Similarly, linear momentum along the Z-axis is converted into angular momentum around the Y-axis and unloaded by the Y-axis rotational damping buffer component. The angular momentum around the X, Y, and Z axes is unloaded by the three sets of rotational damping buffer components around the X, Y, and Z axes, respectively, ultimately achieving the unloading of six-dimensional spatial momentum. The specific principles for momentum unloading in each direction are as follows:

[0030] When the end of the mechanism is subjected to momentum impact in the direction of rotation around the X-axis, the clutch X (310) is in the disengaged state. The angular momentum causes the Y-axis rotating housing (102) to rotate relative to the fixed plate (101). At this time, the torsion spring X (305) will twist to generate a passive buffering effect. The encoder X (312) monitors the motion state and transmits the angular displacement and angular velocity to the controller. The semi-active controller is composed of the designed target control algorithm and the rotary magnetorheological damper X (308). The target control algorithm calculates the desired damping torque for buffering the collision based on the angular displacement and angular velocity. Then, the rotary magnetorheological damper X (308) outputs the corresponding damping torque through electromagnetic control, thereby realizing the unloading control of the impact angular momentum in the direction of rotation of the X-axis.

[0031] When the end of the mechanism is subjected to momentum impact in the direction of rotation around the Y-axis, the clutch Y (205) is in the disengaged state. The angular momentum causes the cross shaft (202) to rotate relative to the second bracket (105) and the fifth bracket (110). At this time, the torsion spring Y (206) will twist to generate a passive buffering effect. The encoder Y (207) monitors the motion state and transmits the angular displacement and angular velocity to the controller. The semi-active controller is composed of the designed target control algorithm and the rotary magnetorheological damper Y (201). The target control algorithm calculates the desired damping torque of the buffer collision based on the motion variables. Then, the rotary magnetorheological damper Y (201) outputs the corresponding damping torque through electromagnetic control, thereby realizing the unloading control of the impact angular momentum in the direction of rotation of the Y-axis.

[0032] When the end of the mechanism is subjected to momentum impact in the direction of rotation around the Z-axis, the clutch Z (209) is in the disengaged state. The angular momentum causes the cross shaft (202) to rotate relative to the support three (106) and support eight (203). At this time, the torsion spring Z (210) will be torsion to generate a passive buffering effect. The encoder Z (207) monitors the motion state and transmits the angular displacement and angular velocity to the controller. The semi-active controller is composed of the designed target control algorithm and the rotary magnetorheological damper Z (204). The target control algorithm calculates the desired damping torque of the buffer collision based on the motion variables. Then, the rotary magnetorheological damper Z (204) outputs the corresponding damping torque through electromagnetic control, thereby realizing the unloading control of the impact angular momentum in the direction of rotation of the Z-axis.

[0033] When the end of the mechanism is impacted by linear momentum along the X-axis, the clutches Z (209) are in a disengaged state. The fixed plate (101) of the mechanism is impacted, causing relative rotation between the cross shaft (202) and the brackets three (106) and eight (203). At this time, the torsion spring Z (210) will twist to produce a passive buffering effect. The encoder Z (207) monitors the motion state and transmits the angular displacement and angular velocity to the controller. The semi-active controller is composed of the designed target control algorithm and the rotary magnetorheological damper Z (204). The target control algorithm calculates the desired damping torque for buffering the collision based on the motion variables. Then, the rotary magnetorheological damper Z (204) outputs the corresponding damping torque through electromagnetic control, thereby realizing the unloading of linear momentum in the X-axis direction.

[0034] When the end of the mechanism is subjected to momentum impact in the linear direction of the Y-axis, the linear momentum impact energy in the linear direction of the Y-axis is converted into angular momentum impact in the rotational direction around the Z-axis because there is a lever arm between the point of force application and the cross axis, thus the momentum is converted and unloaded.

[0035] When the end of the mechanism is subjected to momentum impact in the Z-axis linear direction, the linear momentum impact energy in the Z-axis linear direction is converted into angular momentum impact in the rotational direction around the Y-axis because there is a lever arm between the point of force application and the cross axis, thus the momentum is converted and unloaded.

Claims

1. A three-degree-of-freedom soft docking joint for unloading six-dimensional spatial impulse, comprising a transmission mechanism, a damping buffer assembly, and a sensing assembly: the transmission mechanism includes a fixed plate (101), a Y-axis rotating housing (102), a Z-axis rotating housing (108), a bracket one (103), a bracket two (105), a bracket three (106), a bracket four (107), a bracket five (110), a bracket six (111), a bracket seven (112), a bracket eight (203), a bracket nine (306), a bracket ten (313), a coupling (307), a rotating spindle Z (213), a rotating spindle Y (214), and a rotating spindle X (215). 315), main shaft X fixed fastener (314), deep groove ball bearing one (301), deep groove ball bearing two (303), sleeve (302), clutch X (310), clutch Y (205) and clutch Z (209); the damping buffer assembly includes torsion spring seat X (311), torsion spring seat Y (104), torsion spring seat Z (109), torsion spring fixed fastener X (304), torsion spring fixed fastener Y (208), torsion spring fixed fastener Z (212), torsion spring X (305), torsion spring Y (206), torsion spring Z (210), rotary magnetorheological damper X (308), rotary magnetorheological damper Z (210), and rotary magnetorheological damper Z (210). The system includes a variable damper Y (201), a rotary magnetorheological damper Z (204), a damping shaft X (309), and a cross shaft (202); the sensing components include encoder X (312), encoder Y (207), and encoder Z (211), used for measuring angular displacement and angular velocity during rotational motion around the X, Y, and Z axes; the three-degree-of-freedom soft docking joint has three degrees of freedom for rotation around the X, Y, and Z axes, and the three degrees of freedom do not interfere with each other; the Y-axis rotating housing (102) is connected to the bracket (313), the Y-axis rotating housing (102) is L-shaped, and the rotating joints around the Y and Z axes are positioned relative to the X axis. The three-degree-of-freedom soft docking joint is designed with three sets of rotational damping buffer components to unload the momentum impact during the docking process. Due to the existence of a lever arm between the point of force application and the cross axis, the linear momentum along the X-axis and Y-axis is converted into angular momentum about the Z-axis and unloaded by the Z-axis rotational damping buffer component; the linear momentum along the Z-axis is converted into angular momentum about the Y-axis and unloaded by the Y-axis rotational damping buffer component; the angular momentum about the X-axis, Y-axis and Z-axis is unloaded by the three sets of rotational damping buffer components about the X-axis, Y-axis and Z-axis respectively, ultimately achieving the unloading of six-dimensional momentum in space.

2. A three-degree-of-freedom soft docking joint for unloading six-dimensional impulse in space according to claim 1, characterized in that: The rotary magnetorheological damper Y (201) is mounted on bracket five (110), and the rotary magnetorheological damper Z (204) is mounted on bracket eight (203). The rotation shafts of the rotary magnetorheological dampers Y (201) and Z (204) are served by a cross shaft (202). The rotors of clutches Y (205) and Z (209) are connected to the cross shaft (202) by keys. The stator of clutch Y (205) is connected to bracket two (105), and the stator of clutch Z (209) is connected to bracket three (106). The encoder Y (207) is powered by a torsion... Spring seat Y (104) is connected to bracket two (105), encoder Z (211) is connected to bracket four (107) through torsion spring seat Z (109), and the rotation axis of encoder Y (207) and encoder Z (211) is served by cross shaft (202); one end of the torsion spring Y (206) is connected to cross shaft (202) through torsion spring fastener Y (208), and the other end is connected to torsion spring seat Y (104); one end of the torsion spring Z (210) is connected to cross shaft (202) through torsion spring fastener Z (212), and the other end is connected to torsion spring seat Z (109).

3. A three-degree-of-freedom soft docking joint for unloading six-dimensional impulse in space according to claim 1, characterized in that: The rotary magnetorheological damper X (308) is connected to bracket six (111), and its rotation axis is the damping shaft X (309); the rotor of clutch X (310) is connected to the rotating main shaft X (315) via a key, and its stator is connected to bracket nine (306). Bracket nine (306) is connected to bracket six (111) via bracket seven (112); encoder X (312) is connected to bracket nine (306) via torsion spring seat X (311), and its... The motion axis is the rotating spindle X (315); in addition, the rotating spindle X (315) is connected to the rotating inner shell through the rotating spindle X fastener (314) to achieve synchronous rotation; one end of the torsion spring X (305) is connected to the rotating spindle X (315) through the torsion spring fastener X (304), and the other end is connected to the torsion spring seat X (311); the damping shaft X (309) is connected to the rotating spindle X (315) through the coupling (307) to achieve transmission.

4. A three-degree-of-freedom soft docking joint for unloading six-dimensional impulse in space according to claim 1, characterized in that: Deep groove ball bearing 1 (301) and deep groove ball bearing 2 (303) are installed between the fixed plate (101) and the Y-axis rotating housing (102) to achieve relative rotation.

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