An active continuous telescopic space robot arm joint for on-orbit assembly tasks

Abstract

An active continuous telescopic space robot arm joint for on-orbit assembly tasks relates to the field of space robot technology. The small arm rod housing, the middle arm rod housing and the large arm rod housing are nested step by step from the inside to the outside, and the electromechanical interface is installed at the top of the small arm rod housing and the bottom of the large arm rod housing. The small arm rod housing and the middle arm rod housing are fixed with a locking system at the bottom, and multiple locking petals are radially expanded or contracted to achieve locking or unlocking. The transmission system adopts an active rotary joint transmission screw. The threaded section of the screw cooperates with multiple small arm rod nut assemblies and is evenly fixed inside the small arm rod housing. The cylindrical section of the screw is sleeved with a middle arm rod nut assembly and fixed at the bottom of the middle arm rod housing. The introduction of an active continuous telescopic mechanism allows the robot arm joint to independently and continuously adjust its length within the entire travel range, and can be firmly locked at any position to meet the needs of different on-orbit assembly tasks.

Description

Technical Field

[0001] The invention relates to the technical field of space robots, in particular to an active continuous telescopic space robot arm joint used for on-orbit assembly tasks. Background Art

[0002] Space robots play a key role in on-orbit assembly tasks, and can perform complex operations such as assembly, maintenance, docking and handling in microgravity, vacuum and extreme temperature environments. As the core actuator of space robots, the design of the robotic arm is directly related to the final result of the task, especially in complex and dynamic task environments, where the flexibility, precision and adaptability of the robotic arm are particularly critical.

[0003] At present, although the concept and design of retractable manipulators have been proposed in the R&D plans and academic research of various countries, they have not yet been truly applied in space. Existing space manipulators still mainly adopt fixed length design, or in a few cases adopt non-continuous telescopic design. Although manipulators of this type, such as the next-generation Canadarm3, have a certain length adjustment capability, they can only switch between preset fixed positions and cannot achieve continuous adjustment at any position between these positions. In addition, most of the current retractable manipulators adopt passive telescopic mode, that is, they rely on the movement of other joints to forcibly pull out the arm and stretch it to the preset position. As far as the telescopic joints are concerned, they cannot independently achieve length adjustment. This non-continuous passive telescopic design has certain advantages in structural simplification, control system stability and energy consumption, but it has significant deficiencies in operational flexibility and mission adaptability. Specifically, the manipulator cannot make fine adjustments in the space environment where mission requirements change rapidly, especially when facing tasks that require precise positioning and a large operating range. Its limitations are particularly obvious. This design limits the operating range and flexibility of the robot arm when performing complex and dynamic tasks, and it is difficult to meet the needs of future space assembly tasks with complex structures, huge volumes, harsh installation environments and high precision requirements.

[0004] In summary, with the increasing complexity and diversification of future space exploration missions, space manipulators need to have higher flexibility, precision and adaptability. There is an urgent need for a design of active continuously telescopic space manipulator joints to overcome the limitations of traditional discontinuous telescopic designs, especially the shortcomings of passive discontinuous telescopic designs, so as to provide stronger technical support for future on-orbit assembly missions. Summary of the invention

[0005] In order to address the shortcomings of the background technology, the present invention provides an active continuously telescopic space robot arm joint for on-orbit assembly tasks. By introducing an active continuous telescopic mechanism, the robot arm joint allows the length to be independently and continuously adjusted within the entire travel range, and can be securely locked at any position. It can flexibly expand the working range of the space robot arm, significantly improve the accuracy of operation and task adaptability, so as to meet the needs of different on-orbit assembly tasks.

[0006] To achieve the above object, the present invention adopts the following technical solution: an active continuous telescopic space robot arm joint for on-orbit assembly tasks, comprising

[0007] Arm housing unit, electromechanical interface unit, locking system and transmission system;

[0008] The arm housing unit comprises a small arm housing, a middle arm housing and a large arm housing which are nested step by step from the inside to the outside, and the small arm housing and the middle arm housing can only move along the axis direction;

[0009] The electromechanical interface unit includes a small arm interface installed at the top end of the small arm housing and a large arm interface installed at the bottom end of the large arm housing;

[0010] The number of the locking systems is two and they are coaxially fixed to the bottom of the small arm lever housing and the middle arm lever housing respectively. The locking system comprises a hollow rotating joint and a locking mechanism. The locking mechanism is provided with a plurality of locking petals in an annular direction. The plurality of locking petals can be driven to radially expand or contract through the hollow rotating joint to achieve locking or unlocking of the small arm lever housing and the middle arm lever housing and the middle arm lever housing and the large arm lever housing;

[0011] The transmission system includes an active rotating joint and a screw. The active rotating joint is coaxially fixed at the bottom of the big arm rod housing and connected to the transmission screw. The screw is divided into two parts: a cylindrical section and a threaded section. The threaded section of the screw is screwed together with multiple small arm rod nut assemblies. The multiple small arm rod nut assemblies are evenly fixed inside the small arm rod housing along the axial direction. A middle arm rod nut assembly is sleeved at the position of the adjacent threaded section of the cylindrical section of the screw. The middle arm rod nut assembly is coaxially fixed at the bottom of the middle arm rod housing.

[0012] Furthermore, limiting rings are integrally provided on the outer side of the bottom end of the small arm housing, the inner side of the top end and the outer side of the bottom end of the middle arm housing, and the inner side of the top end of the large arm housing.

[0013] Furthermore, when the small arm rod housing and the middle arm rod housing each reach their maximum extension, they are magnetically fixed to the corresponding middle arm rod housing and the large arm rod housing through an electromagnetic locking unit, and the electromagnetic locking unit includes a pair of matching electromagnets and iron blocks, which are respectively embedded in and fixed to the lower surface of the limit ring at the top end of the middle arm rod housing and the large arm rod housing and the upper surface of the limit ring at the bottom end of the small arm rod housing and the middle arm rod housing.

[0014] Furthermore, real-time position measurement feedback is performed between the small arm housing and the middle arm housing, and between the middle arm housing and the large arm housing through a sensor system, and the sensor system adopts a guide rail direct sliding potentiometer.

[0015] Furthermore, the sensing system also includes paired Hall sensors and permanent magnets, which are respectively embedded in the lower surface of the limit ring fixed at the top of the middle arm rod housing and the large arm rod housing and the upper surface of the limit ring at the bottom of the small arm rod housing and the middle arm rod housing.

[0016] Furthermore, the small arm lever interface and the large arm lever interface both have gender-neutral characteristics.

[0017] Furthermore, winding units are respectively arranged at the lower part of the inner wall of the middle arm rod housing and the large arm rod housing, and the winding units include a bracket, a winding wheel, a torsion spring, a rotating shaft and a lead frame. The bracket is fixed to the arrangement position, the rotating shaft is transversely installed between the corresponding grooves of the two arms of the bracket, the winding wheel is sleeved on the rotating shaft, the torsion spring is installed between the winding wheel and the rotating shaft, and the lead frame is installed on the bracket and a line through hole is preset in the middle position.

[0018] Furthermore, the locking mechanism includes a power nut, a base, a power screw, multiple connecting rods and multiple locking petals. The base body is a cylindrical structure and an annular wing plate is integrally arranged on the outer side of its bottom end. The annular wing plate of the base is connected and fixed to the outer flange of the hollow rotary joint. A plurality of axial grooves are evenly processed on the side wall of the main body of the base, and a plurality of radial grooves are evenly processed on the annular wing plate of the base. The radial grooves correspond to the axial grooves in position one by one. The power screw is coaxially inserted into the interior of the base. The power screw is divided into a cylindrical section and a threaded section. The power nut extends into the interior of the base from the bottom end of the base and is screwed together with the threaded section of the power screw. A flange is arranged on the outer end of the power nut and is connected to the output flange of the hollow rotary joint for transmission. The multiple locking petals are annularly arranged on the outer side of the main body of the base, and a limiting nail is arranged at the center of the bottom end of each locking petal to slide with the corresponding radial groove. The multiple connecting rods pass through the corresponding axial grooves and the two ends are respectively hinged to the middle position of the inner wall of the locking petal and the corresponding position of the cylindrical section side wall of the power screw.

[0019] Furthermore, angle sensors and torque sensors are integrated inside the hollow rotary joint and the active rotary joint.

[0020] Furthermore, the outer walls of the small arm rod housing and the middle arm rod housing are respectively processed with multiple guide protrusions evenly in the circumferential direction, and the guide grooves are axially opened at corresponding positions on the inner walls of the middle arm rod housing and the large arm rod housing, and the rotation of the small arm rod housing and the middle arm rod housing around the axis is limited by the cooperation between the guide protrusions and the corresponding guide grooves.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] 1. The present invention adopts three-section arm housing nesting, and the two inner arm housings can be extended step by step. By carefully arranging the installation position of the nut assembly and the length of the lead screw, it can be ensured that at the same time, at most one section of the arm housing nut assembly is completely screwed and matched with the lead screw. The two-stage telescopic movement has a sequence, is independent of each other, and does not interfere with each other;

[0023] 2. The locking system adopted by the present invention is an internally supported active locking system. The traditional passive locking system can only achieve locking at a certain position, and once locked, it is often impossible to retract, or requires a large external force to retract, and is prone to unlocking and jamming failures. In addition, it is necessary to rely on the spring to continuously apply pressure to the internal arm housing, which increases the friction force, increases the resistance during the movement, increases the wear between components, shortens the service life of components, and reduces the transmission efficiency and reliability of the entire robotic arm system. The locking system of the present invention can effectively avoid the occurrence of the above-mentioned failures. At the same time, the locking petal can also correct and compensate for the flexural deformation of the arm housing during the expansion process, thereby improving the movement accuracy of the entire robotic arm.

[0024] 3. The present invention adopts a locking system provided at the bottom end of the two-section telescopic arm housing, which can realize reliable locking at any position within the length variation range of each section, so that the joint can fix its length at any position within the travel range;

[0025] 4. The transmission system of the present invention adopts screw drive, which can adjust its own length independently without relying on other joints, and greatly improve the bearing capacity, transmission accuracy, transmission efficiency, and overall stiffness of the joints, reduce friction loss in the transmission process, suppress vibration, and increase the reliability and service life of the joints;

[0026] 5. The present invention can detect the joint length in real time through the arrangement of the guide rail direct sliding potentiometer to achieve accurate control of the joint length;

[0027] 6. The present invention equips the top of the arm housing with an electromagnet and a Hall sensor, and the bottom of the corresponding arm housing with a permanent magnet and an iron block. As the arm housing is extended, the distance between the permanent magnet and the Hall sensor gradually approaches to detect whether the arm housing is extended to the maximum length. The electromagnet fixes the iron block through electromagnetic attraction to lock two adjacent arm housings at the maximum length, and cooperates with the locking system to achieve multiple locking at the extreme position, ensuring high reliability under the dangerous working condition of the extreme position. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a schematic diagram of the internal structure of the space manipulator joint of the present invention;

[0029] Figure 2 It is an exploded schematic diagram of the winding unit in the present invention;

[0030] Figure 3 It is a schematic diagram of the assembly position of the electromagnetic locking unit and the transmission system in the present invention;

[0031] Figure 4 It is a schematic diagram of the contraction and expansion state transformation of the locking system in the present invention;

[0032] Figure 5 is an exploded schematic diagram of the locking system of the present invention;

[0033] Figure 6 It is a schematic diagram of the positional relationship between the electromagnetic locking unit and the sensor system in the present invention;

[0034] Figure 7 Schematic diagram of five typical states of the space manipulator joint of the present invention.

[0035] In the figure: 11, small arm housing; 12, middle arm housing; 13, large arm housing; 21, small arm interface; 22, large arm interface; 3, winding unit; 31, bracket; 32, winding wheel; 33, torsion spring; 34, rotating shaft; 35, lead frame; 41, middle arm electromagnet; 42, large arm electromagnet; 43, small arm iron block; 44, middle arm iron block; 5, locking system; 51, hollow rotating joint; 52, locking mechanism; 53, transmission bolt; 54, positioning bolt; 52-1, power nut; 52-2, base; 52-3, cover; 52-4 , power screw; 52-5, connecting rod; 52-6, locking flap; 52-7, pin; 52-8, stopper; 52-9, connecting screw; 52-10, locating pin; 61, active rotary joint; 62, lead screw; 63, adapter; 64, small arm rod nut assembly; 65, middle arm rod nut assembly; 71, small arm rod potentiometer probe; 72, small arm rod potentiometer slide; 73, middle arm rod potentiometer probe; 74, middle arm rod potentiometer slide; 75, small arm rod permanent magnet; 76, middle arm rod Hall sensor; 77, middle arm rod permanent magnet; 78, large arm rod Hall sensor. DETAILED DESCRIPTION

[0036] The technical solution of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0037] like Figure 1 to Figure 7 As shown, an active continuous telescopic space robot arm joint for on-orbit assembly tasks includes an arm housing unit, an electromechanical interface unit, a winding unit 3, an electromagnetic locking unit, a locking system 5, a transmission system and a sensor system.

[0038] Combination Figure 1As shown, the arm housing unit includes a small arm housing 11, a middle arm housing 12 and a large arm housing 13. The arm housing unit is the base of the entire space robot arm joint. The small, medium and large in the small arm housing 11, the middle arm housing 12 and the large arm housing 13 refer to the inner diameter of the corresponding arm, so that the three are nested from the inside to the outside. Among them, the outer side of the bottom end of the small arm housing 11, the inner side of the top end and the outer side of the bottom end of the middle arm housing 12 and the inner side of the top end of the large arm housing 13 are respectively integrally provided with a limit ring to limit the maximum extension of the small arm housing 11 and the middle arm housing 12 to prevent the arm from slipping, and the outer walls of the small arm housing 11 and the middle arm housing 12 are respectively processed with multiple guide protrusions uniformly along the circumferential direction, which are respectively matched with the guide grooves opened along the axial direction at the corresponding positions of the inner walls of the middle arm housing 12 and the large arm housing 13 to limit the rotation of the small arm housing 11 and the middle arm housing 12 around the axis so that they can only move along the axis.

[0039] Combination Figure 1 As shown, the electromechanical interface unit includes a small arm interface 21 and a large arm interface 22. The electromechanical interface unit is used for electromechanical connection between the space manipulator joint and other equipment, has gender-neutral and large tolerance characteristics, and can transmit power and data at the same time. Among them, the small arm interface 21 and the large arm interface 22 are respectively installed at the top of the small arm housing 11 and the bottom of the large arm housing 13.

[0040] Combination Figure 2 As shown, the winding unit 3 includes a bracket 31, a winding wheel 32, a torsion spring 33, a rotating shaft 34 and a lead frame 35. The winding unit 3 is used for winding and arranging the internal lines of the space manipulator joint to prevent the cluttered lines from affecting the normal operation of the space manipulator joint. It can be arranged and installed at two places at the lower part of the inner wall of the middle arm housing 12 and the upper arm housing 13, without affecting the telescopic movement of the small arm housing 11 and the middle arm housing 12. Among them, the bracket 31 is fixed to the layout position, the rotating shaft 34 is horizontally installed between the corresponding sinks of the two arms of the bracket 31, the winding wheel 32 is sleeved on the rotating shaft 34, the torsion spring 33 is installed between the winding wheel 32 and the rotating shaft 34 to provide elastic restoring force, and the lead frame 35 is installed on the bracket 31 and a line through hole is preset in the middle position thereof. When the joint of the space robot arm is not extended, the torsion spring 33 is in an initial state. When the joint of the space robot arm is extended, the torsion angle of the torsion spring 33 increases and stores elastic potential energy. The winding wheel 32 rotates forward, the torque is always balanced, the line passes through the lead frame 35 to be released and is always in a straightened state. When the joint of the space robot arm contracts, the torsion angle of the torsion spring 33 decreases to release the elastic potential energy, driving the winding wheel 32 to rotate in the opposite direction. The torque is always balanced, and the line passes through the lead frame 35 and is also always in a straightened state.

[0041] Combination Figure 3As shown, the electromagnetic locking unit includes a middle arm electromagnet 41, a large arm electromagnet 42, a small arm iron block 43 and a middle arm iron block 44. The electromagnetic locking unit is used to generate magnetic attraction through the electromagnet and the iron block to play an auxiliary locking role when the small arm housing 11 and the middle arm housing 12 reach their respective maximum extensions. In order to ensure the stability of locking, the electromagnet and the iron block are preferably arranged in multiple forms at equal angles along the circumferential direction. Among them, the middle arm electromagnet 41 and the large arm electromagnet 42 are respectively embedded in the lower surface of the limit ring fixed at the top of the middle arm housing 12 and the large arm housing 13, and the small arm iron block 43 and the middle arm iron block 44 are respectively embedded in the upper surface of the limit ring fixed at the bottom of the small arm housing 11 and the middle arm housing 12. The positions of the middle arm electromagnet 41 and the small arm iron block 43 correspond one to one, and the positions of the large arm electromagnet 42 and the middle arm iron block 44 correspond one to one. When the small arm housing 11 moves to the maximum extension length, the upper surface of the limit ring at the bottom of the small arm housing 11 fits with the lower surface of the limit ring at the top of the middle arm housing 12. At this time, the middle arm electromagnet 41 is energized and tightly attracted to the small arm iron block 43 to achieve axial auxiliary locking. Similarly, when the middle arm housing 12 moves to the maximum extension length, the upper surface of the limit ring at the bottom of the middle arm housing 12 fits with the lower surface of the limit ring at the top of the large arm housing 13. At this time, the large arm electromagnet 42 is energized and tightly attracted to the middle arm iron block 44 to achieve axial auxiliary locking.

[0042] Combination Figure 4 As shown, the locking system 5 includes a hollow rotary joint 51, a locking mechanism 52, a transmission bolt 53 and a positioning bolt 54. There are two locking systems 5, which are coaxially fixed to the bottom of the small arm housing 11 and the middle arm housing 12, respectively. The small arm housing 11 and the middle arm housing 12, and the middle arm housing 12 and the large arm housing 13 can be locked at any extension by controlling the expansion action of the locking mechanism 52. Among them, the hollow rotary joint 51 is selected so as not to affect the passage of the lead screw 62 in the transmission system. The hollow rotary joint 51 has an integrated angle sensor and a torque sensor, which can accurately measure and feedback the output rotation angle and torque in real time.

[0043] Combination Figure 5As shown, the locking mechanism 52 is composed of a power nut 52-1, a base 52-2, a cover 52-3, a power screw 52-4, a connecting rod 52-5, a locking flap 52-6, a pin 52-7, a stopper 52-8, a connecting screw 52-9 and a positioning pin 52-10. The main body of the base 52-2 is a cylindrical structure and an annular wing plate is integrally provided on the outer side of its bottom end. A plurality of axial grooves are evenly processed on the side wall of the main body of the base 52-2, and a plurality of radial grooves are evenly processed on the annular wing plate of the base 52-2. The radial grooves correspond to the axial grooves in position. The power screw 52-4 is coaxially inserted into the main body of the base 52-2, and is divided into two parts: a cylindrical section and a threaded section. The power nut 52-1 extends from the bottom end of the base 52-2 into the interior thereof and is screwed together with the threaded section of the power screw 52-4, and has a self-locking characteristic. A flange is provided at the outer end of the power nut 52-1 for connecting and transmitting the hollow rotary joint 51. A plurality of locking petals 52-6 are arranged circumferentially on the outer side of the main body of the base 52-2. Each locking petal 52-6 is connected to the cylindrical section of the power screw 52-4 through a connecting rod 52-5. The connecting rod 52-5 passes through the corresponding axial sliding groove and the two ends of the connecting rod 52-5 are respectively hinged to the holed bosses preset at the middle position of the inner wall of the locking petal 52-6 and the corresponding position of the side wall of the cylindrical section of the power screw 52-4 through pins 52-7. Two connecting rods 52-5 arranged in a flat shape are preferably used between each locking petal 52-6 and the power screw 52-4. A limit pin is provided at the bottom center of each locking petal 52-6 to slide with the corresponding radial sliding groove. In addition, a stopper 52-8 is provided at each hinge point of the cylindrical section side wall of the power screw 52-4 to position the maximum expansion state of the multiple locking petals 52-6 by blocking the connecting rod 52-5. The top of the main body of the base 52-2 can also be designed to be a split form to form a cover 52-3, so as to facilitate the assembly and disassembly of the connecting rod 52-5 and other components. When the cover 52-3 is installed back to the top of the main body of the base 52-2, it is connected by connecting screws 52-9 and positioning pins 52-10. The positioning pins 52-10 are used for positioning during connection. The connecting screws 52-9 connect the cover 52-3 and the base 52-2 into a whole. When the locking mechanism 52 is assembled with the hollow rotary joint 51, the flange plate at the outer end of the power nut 52-1 is connected and fixed to the output flange of the hollow rotary joint 51 through the transmission bolt 53 to transmit the rotational motion output by the joint. The positioning bolt 54 passes through the uniformly preset through holes on the edge of the annular wing plate of the base 52-2 and is connected and fixed to the outer flange of the hollow rotary joint 51, so that the locking mechanism 52 and the hollow rotary joint 51 are fixedly connected as a whole. When the locking system 5 is assembled with the small arm rod housing 11 and the middle arm rod housing 12, the end of the hollow rotary joint 51 is fixed to the bottom of the small arm rod housing 11 and the middle arm rod housing 12 through a special metal adhesive.

[0044] The working principle of the locking system 5 is: during the extension and retraction of the space robot arm joint, the locking mechanism 52 is in an unlocked state, the distance between the power screw 52-4 and the hollow rotating joint 51 reaches the minimum, and the multiple locking petals 52-6 are close together in a ring. At this time, the outer envelope circle diameter of the multiple locking petals 52-6 is the smallest, which is smaller than the maximum outer diameter of the annular wing plate of the base 52-2. In this state, the locking system 5 has no contact with the inner wall of the adjacent arm housing, and there is a large gap, which will not affect the normal extension and retraction of the arm housing connected to it. When the arm housing connected thereto moves to the set position, the control system sends a locking action signal to the locking system 5, and the locking system 5 performs a locking action. At this time, the hollow rotary joint 51 outputs a positive rotational motion, driving the power nut 52-1 in the locking mechanism 52 to rotate together. The internal thread of the power nut 52-1 is screwed with the threaded section of the power screw 52-4. The multiple axial grooves of the base 52-2 limit the rotation of the power screw 52-4 around the axis, so that it can only make a linear motion away from the hollow rotary joint 51 along the axis direction, and at the same time push the multiple connecting rods 52-5 connected thereto. The multiple locking petals 52-6 are restricted by the multiple radial grooves of the base 52-2 and make a linear motion away from the axis along the radial direction through the push of the multiple connecting rods 52-5. In this process, the outer envelope circle diameter of the multiple locking petals 52-6 gradually increases until the diameter is equal to the inner diameter of the adjacent arm housing. The multiple locking petals 52-6 are tangent to the inner wall of the adjacent arm housing and come into contact. When the hollow rotary joint 51 continues to output positive rotational motion, the multiple locking petals 52-6 can be squeezed against the inner wall of the arm housing, and the locking effect is achieved through friction. When the locking force reaches the preset value, the hollow rotary joint 51 stops rotating, and the locking system 5 completes the locking action. When the multiple connecting rods 52-5 are parallel to the annular wing plate of the base 52-2, the outer envelope circle diameter of the multiple locking petals 52-6 reaches the maximum, and the diameter is larger than the inner diameter of the adjacent arm housing, which can ensure that a sufficiently large locking force is generated. In addition, during the extension of the arm housing, the extended arm housing will produce flexural deformation, and the end will "tilt up". During the operation of the locking system 5, since the multiple locking petals 52-6 are evenly distributed along the circumferential direction, the "tilted" side will first contact the adjacent inner wall of the arm housing, thereby correcting and compensating for the flexural deformation and playing the role of fixing the axis. After the locking action of the locking system 5 is completed, the flexural deformation of the extended section of the arm housing will be significantly compensated, which improves the lack of rigidity to a certain extent. When the arm housing needs to be further extended or retracted, the control system sends an unlocking action command to the locking system 5, controlling the hollow rotary joint 51 to output a reverse rotational motion until the multiple locking petals 52-6 are again abutted against each other to form a ring, and the unlocking action is completed.

[0045] Combination Figure 3As shown, the transmission system includes an active rotary joint 61, a lead screw 62, an adapter 63, a small arm nut assembly 64 and a middle arm nut assembly 65. The transmission system adopts a roller screw transmission, which is used for the telescopic control of the small arm housing 11 and the middle arm housing 12, and the active rotary joint 61 also integrates an angle sensor and a torque sensor, which can accurately measure and feedback the output rotation angle and torque in real time. Among them, the active rotary joint 61 is coaxially fixed at the bottom of the large arm housing 13, the lead screw 62 is coaxially arranged inside the large arm housing 13 and passes through two locking systems 5, and the bottom end of the lead screw 62 is connected to the output end of the active rotary joint 61 through the adapter 63, and the torque output by the active rotary joint 61 is transmitted to the lead screw 62. The lead screw 62 is divided into two parts: a cylindrical section and a threaded section. The threaded section parameters are unique and have self-locking characteristics. There are multiple small arm rod nut assemblies 64, which are uniformly fixed inside the small arm rod housing 11 along the axial direction thereof, and there is one middle arm rod nut assembly 65, which is coaxially fixed at the bottom position inside the middle arm rod housing 12. When the space manipulator joint is in a fully retracted state, multiple small arm rod nut assemblies 64 are screwed together with the threaded section of the lead screw 62, which helps to reduce the vibration of the lead screw 62 during the launch process and improve the rigidity and reliability of the space manipulator joint under this extreme working condition, while the middle arm rod nut assembly 65 is sleeved on the position of the adjacent threaded section on the cylindrical section of the lead screw 62.

[0046] The telescopic principle of the space manipulator joint is:

[0047] When the space robot arm joint receives an extension command, the locking system 5 installed at the bottom of the small arm rod housing 11 performs an unlocking action. After unlocking, the active rotary joint 61 outputs a positive rotational motion, which is transmitted to the lead screw 62 via the adapter 63 to drive its positive rotation, driving the multiple small arm rod nut assemblies 64 screwed together with it to produce a linear motion axially away from the active rotary joint 61, thereby realizing the extension of the small arm rod housing 11. As the extension length of the small arm rod housing 11 increases, the participating small arm rod nut assemblies 64 disengage from the lead screw 62 one by one. When it is detected that the small arm rod housing 11 has moved to the maximum length, the control system sends a stop command to the active rotary joint 61. At this time, the middle arm rod electromagnet 41 is energized to magnetically fix the small arm rod iron block 43 on the limiting ring at the bottom end of the small arm rod housing 11, and the locking system 5 at the bottom of the small arm rod housing 11 performs a locking action, fixing the small arm rod housing 11 and the middle arm rod housing 12 together by magnetic attraction and friction. At the same time, before the last small arm rod nut assembly 64 in the small arm rod housing 11 is about to completely detach from the screw 62, the middle arm rod nut assembly 65 originally located on the cylindrical section of the screw 62 is screwed into the bottom end of the threaded section of the screw 62, completing the "handover" between the small arm rod nut assembly 64 and the middle arm rod nut assembly 65. Subsequently, the locking system 5 installed at the bottom of the middle arm housing 12 performs the unlocking action. After the unlocking is completed, the control system sends a forward rotation command to the active rotary joint 61, and the lead screw 62 continues to rotate and drives the middle arm nut assembly 65 that is screwed to it to produce a linear motion away from the active rotary joint 61 along the axial direction, so that the middle arm housing 12 extends with the small arm housing 11. When it is detected that the middle arm housing 12 moves to the maximum length, the control system sends a stop command to the active rotary joint 61, and the active rotary joint 61 stops rotating. At this time, the large arm electromagnet 42 is energized to magnetically fix the middle arm iron block 44 on the limit ring at the bottom end of the middle arm housing 12, and the locking system 5 at the bottom of the middle arm housing 12 performs a locking action, fixing the middle arm housing 12 and the large arm housing 13 together by magnetic attraction and friction. The small arm housing 11 and the middle arm housing 12 are fully extended, and the space manipulator joint is in a fully extended state. Similarly, the reverse operation can restore the space manipulator joint to a fully retracted state, and the two locking systems 5 can lock the small arm rod housing 11 and the middle arm rod housing 12 at any extension, thereby realizing the active and continuous extension and retraction of the space manipulator joint at any length positioning.

[0048] Combination Figure 1 , Figure 6As shown, the sensing system includes a small arm potentiometer probe 71, a small arm potentiometer slide 72, a middle arm potentiometer probe 73, a middle arm potentiometer slide 74, a small arm permanent magnet 75, a middle arm Hall sensor 76, a middle arm permanent magnet 77 and a large arm Hall sensor 78. The small arm potentiometer probe 71 is slidably matched with the small arm potentiometer slide 72, the middle arm potentiometer probe 73 is slidably matched with the middle arm potentiometer slide 74, the small arm potentiometer probe 71 and the middle arm potentiometer probe 73 are respectively fixed to the annular wing plate edge of the base 52-2 in the locking mechanism 5 at the bottom end of the small arm housing 11 and the middle arm housing 12, and the small arm potentiometer slide 72 and the middle arm potentiometer slide 74 are respectively fixed to the corresponding positions of the inner wall of the middle arm housing 12 and the large arm housing 13 along the axial direction. During the extension period, the small arm housing 11 drives the small arm potentiometer probe 71 to move along the small arm potentiometer slide rail 72 to measure and feedback its position in real time. During the extension period, the middle arm housing 12 drives the middle arm potentiometer probe 73 to move along the middle arm potentiometer slide rail 74 to measure and feedback its position in real time. The small arm permanent magnet 75, the middle arm Hall sensor 76, the middle arm permanent magnet 77 and the large arm Hall sensor 78 are preferably arranged in multiple equal angles along the circumferential direction. The small arm rod permanent magnet 75 and the middle arm rod permanent magnet 77 are respectively embedded in the upper surface of the limit ring at the bottom end of the small arm rod housing 11 and the middle arm rod housing 12. In order to avoid conflicts with the small arm rod iron block 43 and the middle arm rod iron block 44, the small arm rod permanent magnet 75 is staggered with the small arm rod iron block 43, the middle arm rod permanent magnet 77 is staggered with the middle arm rod iron block 44, and the middle arm rod Hall sensor 76 and the large arm rod Hall sensor 78 are respectively embedded in the middle arm rod housing 11 and the middle arm rod housing 12. In order to avoid conflict with the position of the middle arm electromagnet 41 and the big arm electromagnet 42, the middle arm Hall sensor 76 is arranged alternately with the middle arm electromagnet 41, and the big arm Hall sensor 78 is arranged alternately with the big arm electromagnet 42 on the lower surface of the limit ring at the top of the rod housing 12 and the big arm rod housing 13. At the same time, it is ensured that the small arm permanent magnet 75 corresponds to the middle arm Hall sensor 76, and the middle arm permanent magnet 77 corresponds to the big arm Hall sensor 78. The middle arm Hall sensor 76 and the large arm Hall sensor 78 are mainly used as proximity sensors. As the small arm housing 11 and the middle arm housing 12 extend, the small arm permanent magnet 75 gradually approaches the middle arm Hall sensor 76, and the middle arm permanent magnet 77 gradually approaches the large arm Hall sensor 78, resulting in an increase in the magnetic field intensity sensed by the middle arm Hall sensor 76 and the large arm Hall sensor 78, thereby causing an increase in their output signals until the system setting value is reached. The system determines that the small arm housing 11 and the middle arm housing 12 have been extended to the maximum length. The potentiometer alone can also detect whether the arm housing has been extended to the maximum length. The introduction of the Hall sensor is a supplement and backup for the potentiometer displacement detection, and plays a "safety" role in triggering the locking action of the locking system 5 after the arm housing is extended to the maximum length.

[0049] Combination Figure 7 As shown, five typical states of the space manipulator joint are displayed. It can be seen that the space manipulator joint can continuously adjust the length within the travel range and can be firmly locked at any position.

[0050] Before the space manipulator joint of the present invention leaves the factory, the parameter calibration of each internal sensor and the joint adjustment and testing of each part will be completed to ensure the accurate output of force and position under actual working conditions. In particular, the joint calibration between the displacement measurement sensor of the small arm (mainly composed of the small arm potentiometer probe 71 and the small arm potentiometer slide 72), the displacement sensor of the middle arm (mainly composed of the middle arm potentiometer probe 73 and the middle arm potentiometer slide 74) and the angle sensor in the active rotary joint 61 can cross-verify the direct measurement and indirect measurement of the displacement of the corresponding arm housing, thereby improving the accuracy and reliability of displacement measurement. After being launched into orbit, it is stored in the payload package as a joint module. When the robot or robotic arm performing an on-orbit assembly task needs to be equipped with the joint, the genderless electromechanical interface of the robot or robotic arm to be installed will be detached, and the original joint module or tool will be put back into the payload package, and then connected to the big arm rod interface 22 to complete the installation of the joint. If other joints, tools, and loads still need to be installed after the joint is installed, the entire robot or robotic arm can be controlled to dock the remaining joints, tools, and loads to be installed on the small arm rod interface 21.

[0051] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other forms of assembly without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered in all respects as exemplary and non-restrictive, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations within the meaning and range of equivalents of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

[0052] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. An active continuous telescopic space robot arm joint for on-orbit assembly tasks, characterized by: It comprises an arm housing unit, an electromechanical interface unit, a locking system (5) and a transmission system; The arm housing unit comprises a small arm housing (11), a middle arm housing (12) and a large arm housing (13) which are nested from inside to outside, and the small arm housing (11) and the middle arm housing (12) can only move along the axial direction; The electromechanical interface unit comprises a small arm interface (21) installed at the top end of the small arm housing (11) and a large arm interface (22) installed at the bottom end of the large arm housing (13); The number of the locking systems (5) is two and they are coaxially fixed to the bottom of the small arm housing (11) and the middle arm housing (12), respectively. The locking system (5) comprises a hollow rotating joint (51) and a locking mechanism (52). The locking mechanism (52) is provided with a plurality of locking petals (52-6) in an annular direction. The hollow rotating joint (51) can drive the plurality of locking petals (52-6) to radially expand or contract, thereby realizing the locking or unlocking of the small arm housing (11) and the middle arm housing (12) and the middle arm housing (12) and the large arm housing (13). The transmission system comprises an active rotating joint (61) and a lead screw (62); the active rotating joint (61) is coaxially fixed to the bottom of the large arm housing (13) and connected to the transmission lead screw (62); the lead screw (62) is divided into two parts, a cylindrical section and a threaded section; the threaded section of the lead screw (62) is screwed to cooperate with a plurality of small arm nut assemblies (64); the plurality of small arm nut assemblies (64) are uniformly fixed inside the small arm housing (11) along the axial direction; a middle arm nut assembly (65) is sleeved at the position of the cylindrical section adjacent to the threaded section of the lead screw (62); the middle arm nut assembly (65) is coaxially fixed to the bottom of the middle arm housing (12).

2. The active continuous telescopic space robot arm joint for on-orbit assembly tasks according to claim 1, characterized in that: Limiting rings are integrally arranged on the outer side of the bottom end of the small arm housing (11), the inner side of the top end and the outer side of the bottom end of the middle arm housing (12), and the inner side of the top end of the large arm housing (13).

3. The active continuous telescopic space robot arm joint for on-orbit assembly tasks according to claim 2, characterized in that: When the small arm lever housing (11) and the middle arm lever housing (12) each reach their maximum extension, they are magnetically fixed to the corresponding middle arm lever housing (12) and the large arm lever housing (13) through an electromagnetic locking unit, wherein the electromagnetic locking unit comprises a pair of matched electromagnets and iron blocks, which are respectively embedded in and fixed to the lower surface of the limit ring at the top end of the middle arm lever housing (12) and the large arm lever housing (13) and the upper surface of the limit ring at the bottom end of the small arm lever housing (11) and the middle arm lever housing (12).

4. The active continuous telescopic space robot arm joint for on-orbit assembly tasks according to claim 2, characterized in that: Real-time position measurement feedback is performed between the small arm housing (11) and the middle arm housing (12) and between the middle arm housing (12) and the large arm housing (13) through a sensor system, and the sensor system uses a guide rail direct sliding potentiometer.

5. The active continuous telescopic space robot arm joint for on-orbit assembly tasks according to claim 4, characterized in that: The sensing system also includes a pair of Hall sensors and permanent magnets, which are respectively embedded in the lower surface of the limit ring fixed at the top of the middle arm housing (12) and the large arm housing (13) and the upper surface of the limit ring at the bottom of the small arm housing (11) and the middle arm housing (12).

6. The active continuous telescopic space robot arm joint for on-orbit assembly tasks according to claim 1, characterized in that: The small arm lever interface (21) and the large arm lever interface (22) both have gender-neutral characteristics.

7. The active continuous telescopic space robot arm joint for on-orbit assembly tasks according to claim 1, characterized in that: The winding units (3) are arranged at the lower parts of the inner walls of the middle arm housing (12) and the large arm housing (13), respectively. The winding units (3) include a bracket (31), a winding wheel (32), a torsion spring (33), a rotating shaft (34) and a lead frame (35). The bracket (31) is fixed to the arrangement position, the rotating shaft (34) is transversely installed between the corresponding sink grooves of the two arms of the bracket (31), the winding wheel (32) is sleeved on the rotating shaft (34), the torsion spring (33) is installed between the winding wheel (32) and the rotating shaft (34), and the lead frame (35) is installed on the bracket (31) and a line through hole is preset in the middle position thereof.

8. The active continuous telescopic space robot arm joint for on-orbit assembly tasks according to claim 1, characterized in that: The locking mechanism (52) comprises a power nut (52-1), a base (52-2), a power screw (52-4), a plurality of connecting rods (52-5) and a plurality of locking petals (52-6); the main body of the base (52-2) is a cylindrical structure and an annular wing plate is integrally arranged on the outer side of the bottom end thereof; the annular wing plate of the base (52-2) is connected and fixed to the outer flange of the hollow rotary joint (51); a plurality of axial sliding grooves are evenly processed on the main body side wall of the base (52-2); a plurality of radial sliding grooves are evenly processed on the annular wing plate of the base (52-2); the radial sliding grooves correspond to the axial sliding grooves in position one by one; the power screw (52-4) is coaxially inserted into the base (52-2); the power screw (5 2-4) is divided into two parts, a cylindrical section and a threaded section. The power nut (52-1) extends from the bottom end of the base (52-2) into the interior thereof and is screwed together with the threaded section of the power screw (52-4). A flange is arranged at the outer end of the power nut (52-1) to be connected to the output flange of the hollow rotary joint (51) for transmission. The multiple locking petals (52-6) are circumferentially arranged on the outer side of the main body of the base (52-2), and a limiting pin is arranged at the center of the bottom end of each locking petal (52-6) to slide with the corresponding radial groove. The multiple connecting rods (52-5) pass through the corresponding axial grooves and the two ends are respectively hinged to the middle position of the inner wall of the locking petal (52-6) and the corresponding position of the side wall of the cylindrical section of the power screw (52-4).

9. The active continuous telescopic space robot arm joint for on-orbit assembly tasks according to claim 1, characterized in that: Angle sensors and torque sensors are integrated inside the hollow rotary joint (51) and the active rotary joint (61).

10. The active continuous telescopic space robot arm joint for on-orbit assembly tasks according to claim 1, characterized in that: The outer walls of the small arm housing (11) and the middle arm housing (12) are respectively processed with a plurality of guide protrusions evenly along the circumferential direction, and the inner walls of the middle arm housing (12) and the large arm housing (13) are provided with guide grooves along the axial direction at corresponding positions, and the guide protrusions cooperate with the corresponding guide grooves to limit the rotation of the small arm housing (11) and the middle arm housing (12) around the axis.

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