Space manipulator with reconfigurable working space

Abstract

The invention discloses a space manipulator with a reconfigurable working space, and belongs to the technical field of space manipulator design. The space manipulator comprises a first end effector, a first joint, a first connecting rod, a second joint, a second connecting rod, a third joint, a first telescopic arm rod, a third connecting rod, a fourth joint, a fourth connecting rod, a second telescopic arm rod, a fifth joint, a fifth connecting rod, a sixth joint, a sixth connecting rod, a seventh joint and a second end effector which are connected in sequence. The first telescopic arm rod and the second telescopic arm rod are both telescopic arm rods, the working space of the mechanical arm and the range of the flexible working space are adjusted by changing the lengths of the two arm rods, reconstruction of the working space and the flexible working space is achieved, and the problem that the working capacity is limited in the limited installation space is effectively solved.

Description

Technical Field

[0001] The invention relates to a space robot arm with reconfigurable working space, belonging to the technical field of space robot arm design. Background Art

[0002] The space manipulator itself is an intelligent robot with precise operation and visual recognition capabilities. It has both autonomous analysis capabilities and can be remotely controlled by astronauts. It is a high-end aerospace equipment that integrates mechanics, vision, dynamics, electronics, and control. The space manipulator is usually composed of joints, arm rods, and end effectors. It is a series structure. In most cases, the end of the manipulator reaches the specified position by driving each joint to further complete the on-orbit mission.

[0003] At present, there are relevant research results in this field at home and abroad, but the space manipulator usually needs to complete the operation task in a flexible working space. The range of the flexible working space is limited by the length of the arm, and the length of the space manipulator is fixed, so it is difficult to meet the requirements of working in a large range in a limited installation space. An effective solution to this problem is to make the arm have a telescopic function. Chinese patent CN211590188U proposes a foldable and telescopic space manipulator, which adopts a screw nut transmission scheme. The motor drives the screw to rotate and further promotes the inner arm to complete the telescopic movement. Although the arm has a telescopic function, it adopts a one-level telescopic scheme, so there are problems of low telescopic efficiency and small expansion and contraction ratio. Chinese patent CN102619945A proposes a multi-stage hollow screw synchronous transmission telescopic manipulator, which adopts a multi-stage synchronous hollow screw transmission method. Although it has a large expansion and contraction ratio and high telescopic efficiency, it cannot meet the requirements of routing between joints of the serial manipulator, and the overall structure is not compact enough. Summary of the invention

[0004] The technical problem solved by the present invention is: to overcome the shortcomings of the prior art and propose a spatial robot arm with a reconfigurable workspace. By changing the length of the arm, the workspace of the robot arm and the range of the flexible workspace are adjusted to achieve reconstruction of the workspace and the flexible workspace, effectively solving the problem of limited working capacity under limited installation space.

[0005] The technical solution of the present invention is:

[0006] A spatial manipulator with a reconfigurable workspace comprises a first end effector, a first joint, a first connecting rod, a second joint, a second connecting rod, a third joint, a first telescopic arm, a third connecting rod, a fourth joint, a fourth connecting rod, a second telescopic arm, a fifth joint, a fifth connecting rod, a sixth joint, a sixth connecting rod, a seventh joint and a second end effector connected in sequence;

[0007] The first end effector is connected to the first connecting rod via a first joint, and the first connecting rod can rotate relative to the first end effector under the drive of the first joint;

[0008] The first connecting rod and the second connecting rod are connected via a second joint, and the second connecting rod can rotate relative to the first connecting rod under the drive of the second joint;

[0009] The second connecting rod is connected to the first telescopic arm through a third joint, and the first telescopic arm can rotate relative to the second connecting rod under the drive of the third joint;

[0010] The first telescopic arm is fixedly connected to the third connecting rod by bolts; the third connecting rod is connected to the fourth connecting rod by a fourth joint, and the fourth connecting rod can rotate relative to the third connecting rod under the drive of the fourth joint;

[0011] The fourth connecting rod is fixedly connected to the second telescopic arm by bolts; the second telescopic arm is connected to the fifth connecting rod by a fifth joint, and the fifth connecting rod can rotate relative to the second telescopic arm under the drive of the fifth joint;

[0012] The fifth connecting rod is connected to the sixth connecting rod through a sixth joint, and the sixth connecting rod can rotate relative to the fifth connecting rod under the drive of the sixth joint;

[0013] The sixth connecting rod is connected to the second end effector via a seventh joint, and the second end effector can rotate relative to the sixth connecting rod under the drive of the seventh joint.

[0014] Furthermore, the first telescopic arm and the second telescopic arm can both independently perform telescopic movements to change the length of the arms.

[0015] Furthermore, the first telescopic arm and the second telescopic arm have the same structure, and both include a driver, an encoder, a motor, a support seat, a first nut, a first lead screw, a first nut sleeve, a first end cover, a first bearing, a second nut, a second nut sleeve, a second lead screw, a first arm, a second arm, a third arm, a second bearing and a connecting piece;

[0016] The first end cover is a hollow boss structure, the bottom surface of which is fixed to the inner flange of the upper end surface of the columnar structure below the support seat; the driver is installed on the bottom surface of the first end cover;

[0017] The first screw and the second screw are connected in sequence without relative rotation; the two screws have the same structure, both comprising a first shaft section, a second shaft section, and a third shaft section connected in sequence, and the tail end of the third shaft section is a threaded structure; the first bearing is installed on the first shaft section of the second screw, and the second bearing is installed on the second shaft section of the second screw;

[0018] The first nut is installed in cooperation with the first lead screw, and the second nut is installed in cooperation with the second lead screw. When the first lead screw and the second lead screw rotate, the first nut and the second nut move along the axis of the lead screw.

[0019] The first arm, the second arm and the third arm are sleeved from outside to inside; the tail end of the third arm is fixedly connected to the connecting piece, and the connecting piece is connected to the third connecting rod;

[0020] The first nut sleeve is installed on the first nut and is connected to the first arm and the second arm respectively; the second nut sleeve is installed on the second nut and is connected to the second arm and the third arm;

[0021] The encoder comprises a rotating end and an encoder fixed end, wherein the encoder fixed end is mounted on the protruding surface of the first end cover; the encoder rotating end is fixed to the first shaft end of the first lead screw and rotates synchronously therewith;

[0022] The support seat is two columnar structures connected up and down, the upper end surface of the lower columnar structure has an inner flange, the upper end surface of the upper columnar structure has an outer flange convex structure, and the upper columnar structure is connected to the third joint;

[0023] The motor stator is fixedly connected to the inner wall of the cylindrical structure below the support seat, and the rotor is fixedly connected to the second shaft section of the first lead screw.

[0024] Furthermore, a pair of angular contact bearings are provided, including a first angular contact bearing and a second angular contact bearing, which are respectively installed on the first shaft section and the third shaft section of the first screw, wherein the first angular contact bearing is axially pressed by the end face of the first end cover and the shoulder of the second shaft section of the first screw, and the second angular contact bearing is axially pressed by the shoulder of the third shaft section of the first screw and the support seat.

[0025] Furthermore, a fixing nut is provided, and the fixing nut and the shoulder of the first shaft section of the second lead screw fix the first bearing to prevent the first bearing from moving in the axial direction.

[0026] Furthermore, a number of through holes are evenly distributed on the first nut, and a groove is provided in the first arm; the first nut sleeve is formed by connecting two upper and lower circular rings of different sizes, and the upper surface of the bottom circular ring has a flange, and the flange is provided with threaded holes, which are installed in coordination with the corresponding through holes of the first nut; a plurality of evenly distributed keys are provided on the outer periphery of the bottom circular ring, and each key is installed in coordination with the grooves evenly distributed in the first arm; a threaded hole is provided on the side wall of the circular ring located at the upper part, which is installed in coordination with the through holes on the second arm.

[0027] Furthermore, it also includes a fixing ring, which is installed in the radial direction of the second bearing, the inner wall of the fixing ring matches the outer diameter of the second bearing, and the outer wall of the fixing ring contacts the inner arm of the third arm rod to play a supporting role.

[0028] Furthermore, a threaded hole is provided on the protruding surface of the first end cover, and a circumferentially arranged threaded hole and a through hole are provided on the bottom surface, and the threaded holes on the bottom surface are all located outside the through holes; a through hole is provided on the driver, and the through hole is installed in cooperation with the threaded hole on the bottom surface of the first end cover; a through hole is provided on the fixed end of the encoder, and the through hole is installed in cooperation with the threaded hole on the protruding surface of the first end cover.

[0029] Furthermore, it also includes a second end cover and a third end cover, the second end cover is fixed to the first nut sleeve, and the third end cover is fixed to the second lead screw.

[0030] Furthermore, the space robot arms are symmetrically distributed around the fourth joint.

[0031] The advantages of the present invention compared with the prior art are:

[0032] (1) The present invention adopts a two-stage synchronous telescopic design of the arm, and a single motor can drive the second arm and the third arm to synchronously telescope, ensuring that the arm of the robot has a larger extension and retraction ratio and a faster telescopic speed.

[0033] (2) The present invention designs two pairs of bearing support structures. When extending and retracting, the lead screw is always supported by the two pairs of bearings, which effectively avoids the appearance of a cantilever beam structure and ensures that the arm has strong rigidity.

[0034] (3) The present invention proposes a hollow wiring structure: since the length of the arm is variable during the telescopic process, this requires that the length of the cable be stretched when the arm is extended, and can be actively shortened when the arm is retracted. Therefore, the cable selects an elastic spiral wire and runs from the center of the screw.

[0035] (4) The robot arm designed in the present invention has a symmetrical configuration, and the symmetrical structure of the fourth joint of the robot arm further enhances the versatility of the robot arm.

[0036] (5) The present invention proposes an embedded design of the first telescopic arm and the second telescopic arm, in which the motor, the driver, and the encoder are embedded in the support base, making the structure of the first telescopic arm and the second telescopic arm more compact.

[0037] (6) The present invention reconstructs the working space of the robot arm and can expand the working space and the range of the flexible working space of the robot arm by changing the length of the arm rod. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Various other advantages and benefits will become apparent to those of ordinary skill in the art by reading the detailed description of the preferred embodiments below. The accompanying drawings are only for the purpose of illustrating the preferred embodiments and are not to be considered as limiting the present invention. Moreover, the same reference symbols are used throughout the accompanying drawings to represent the same components. In the accompanying drawings:

[0039] Figure 1This is a schematic diagram of the structure of a space robot arm according to an embodiment of the present invention;

[0040] Figure 2 This is a schematic diagram of the structure of a first telescopic arm according to an embodiment of the present invention;

[0041] Figure 3 This is a schematic diagram of the connection relationship of the first end cover of the retractable arm according to an embodiment of the present invention;

[0042] Figure 4 A schematic diagram of an encoder according to an embodiment of the present invention;

[0043] Figure 5 This is a schematic diagram of a first lead screw according to an embodiment of the present invention;

[0044] Figure 6 This is a schematic diagram of the connection of the first lead screw according to an embodiment of the present invention;

[0045] Figure 7 This is a schematic diagram of a first nut sleeve according to an embodiment of the present invention;

[0046] Figure 8 This is a schematic diagram of the connection of the second lead screw according to an embodiment of the present invention;

[0047] Fig. 9 This is a schematic diagram of a second nut sleeve according to an embodiment of the present invention;

[0048] Fig.10 This is a partial diagram of the second lead screw in an embodiment of the present invention;

[0049] Fig.11 This is a schematic diagram of a first arm according to an embodiment of the present invention;

[0050] Fig.12 This is a schematic diagram of a second arm lever according to an embodiment of the present invention;

[0051] Fig.13 This is a schematic diagram of a third arm according to an embodiment of the present invention;

[0052] Fig.14 This is a schematic diagram of the end surface structure of the first lead screw and the second lead screw in an embodiment of the present invention;

[0053] Fig.15 This is a schematic diagram of the connection between the third arm and the connecting member according to an embodiment of the present invention;

[0054] Fig.16 This is a schematic diagram of the arrangement of the spools according to an embodiment of the present invention;

[0055] Fig.17 Schematic diagram of the working space and flexible working space of the robot arm according to an embodiment of the present invention. DETAILED DESCRIPTION

[0056] The exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although the exemplary embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided to enable a more thorough understanding of the present disclosure and to fully convey the scope of the present disclosure to those skilled in the art.

[0057] The present invention proposes a space robot arm with reconfigurable working space, such as Figure 1 As shown, it includes a first end effector 1, a first joint 2, a first link 3, a second joint 4, a second link 5, a third joint 6, a first telescopic arm 7, a fourth link 8, a fourth joint 9, a third link 10, a second telescopic arm 11, a fifth joint 12, a fifth link 13, a sixth joint 14, a sixth link 15, a seventh joint 16, and a second end effector 17, which are symmetrically distributed with the fourth joint 9 as the center.

[0058] The first end effector 1 is connected with the first link 3 through the first joint 2, and the first link 3 can rotate relative to the first end effector 1 under the drive of the first joint 2. The first link 3 is connected with the second link 5 through the second joint 4, and the second link 5 can rotate relative to the first link 3 under the drive of the second joint 4. The second link 5 is connected with the first telescopic arm 7 through the third joint 6, and the first telescopic arm 7 can rotate relative to the second link 5 under the drive of the third joint 6. The first telescopic arm 7 is fixedly connected with the third link 10 through bolts. The third link 10 is connected with the fourth link 8 through the fourth joint 9, and the fourth link 8 can rotate relative to the third link 10 under the drive of the fourth joint 9. The fourth link 8 is fixedly connected with the second telescopic arm 11 through bolts. The second telescopic arm 11 is connected with the fifth link 13 through the fifth joint 12, and the fifth link 13 can rotate relative to the second telescopic arm 11 under the drive of the fifth joint 12. The fifth link 13 is connected to the sixth link 15 through the sixth joint 14, and the sixth link 15 can rotate relative to the fifth link 13 under the drive of the sixth joint 14. The sixth link 15 is connected to the second end effector 17 through the seventh joint 16, and the second end effector 17 can rotate relative to the sixth link 15 under the drive of the seventh joint 16.

[0059] The first telescopic arm 7 has the same structure as the second telescopic arm 11, and the first telescopic arm 7 is taken as an example for description. Figure 2As shown, the first telescopic arm 7 includes a driver 7-1, an encoder 7-2, a first end cover 7-3, a first angular contact bearing 7-4, a motor 7-5, a support seat 7-6, a second angular contact bearing 7-7, a first nut 7-8, a first screw 7-9, a first nut sleeve 7-10, a fixing nut 7-11, a first bearing 7-12, a second end cover 7-13, a second nut 7-14, a second nut sleeve 7-15, a second screw 7-16, a first arm 7-17, a second arm 7-18, a third arm 7-19, a fixing ring 7-20, a second bearing 7-21, a third end cover 7-22, and a connecting piece 7-23.

[0060] The driver 7-1 has three evenly distributed through holes 7-101 that are mounted in cooperation with the threaded holes 7-302 on the first end cover 7-3. Figure 3 As shown, the first end cover 7-3 has six evenly distributed through holes 7-303 which are installed in cooperation with the threaded holes 7-601 on the support seat 7-6. The encoder 7-2 is as shown in FIG. Figure 4 As shown, it can be divided into an encoder rotating end 7-202 and an encoder fixed end 7-203. Three through holes 7-201 are evenly distributed on the fixed end and are installed in coordination with the threaded holes 7-301 on the first end cover 7-3. Three threaded holes 7-204 are evenly distributed on the encoder rotating end 7-202 and are fixed to the first shaft end 7-901 of the first lead screw 7-9 through top screws and rotate synchronously therewith. Figure 5 The motor 7-5 is divided into a rotor and a stator, wherein the stator part is glued and fixedly connected to the inner arm 7-601 of the support seat 7-6, and the rotor part is glued and fixedly connected to the second shaft section 7-902 of the first lead screw 7-9. When working, the rotor will drive the first lead screw 7-9 to rotate.

[0061] The first angular contact bearing 7-4 and the second angular contact bearing 7-7 are a pair of angular contact bearings, which are respectively installed on the first shaft section 7-901 and the third shaft section 7-904 of the first screw 7-9, wherein the first angular contact bearing 7-4 is axially pressed by the right end face of the first end cover 7-3 and the left shoulder of the second shaft section 7-902, and the second angular contact bearing 7-7 is axially pressed by the right end face of the shoulder 7-903 of the first screw 7-9 and the support seat 7-6 to prevent axial movement. In addition, the angular contact bearings are installed in conjunction with the first screw 7-9 to play a supporting role.

[0062] The first screw 7-9 is installed in cooperation with the first nut 7-8. Figure 6 As shown, when the first screw rotates, the first nut will move along the screw axis. Figure 7As shown, the first nut sleeve is formed by connecting two circular rings of different sizes, the upper surface of the bottom circular ring is provided with a flange, and six threaded holes 1001 are evenly distributed on the flange, which are installed in conjunction with the corresponding through holes 7-801 of the first nut; four evenly distributed keys 7-1002 are provided on the outer periphery of the bottom circular ring, and each key is installed in conjunction with the evenly distributed grooves 7-1702 in the first arm, as shown in FIG. Fig.11 As shown, the first nut sleeve and the first arm are prevented from rotating relative to each other. A threaded hole 7-1003 is provided on the side wall of the upper ring, which is installed in coordination with the through hole 7-1801 on the second arm. Fig.12 The second lead screw is as shown. Figure 8 As shown, the fixing nut 7-11 and the first bearing 7-12 are installed on the first shaft section 7-1601 of the second screw 7-16, and the fixing nut and the shaft shoulder of the first shaft section fix the first bearing to prevent the first bearing from moving in the axial direction. The six through holes 7-1301 evenly distributed on the second end cover 7-13 are matched with the threaded holes 7-1004 evenly distributed on the upper end surface of the circular ring on the first nut sleeve 7-10 to fix the second screw 7-16 and the first nut sleeve 7-10.

[0063] The cross section 7-905 of the first screw 7-9 is installed in cooperation with the cross section 7-1603 of the second screw 7-16. Fig.10 , Fig.14 As shown, it is ensured that there is no relative rotation between the first screw and the second screw. The second screw 7-16 is installed in conjunction with the second nut 7-14. When the second screw rotates, the second nut will move along the axis of the screw. The six through holes 7-1401 evenly distributed on the second nut 7-14 are installed in conjunction with the threaded holes 7-1501 evenly distributed on the first nut sleeve 7-15. The second nut sleeve is as shown in FIG. Fig. 9 As shown, the structure is the same as the first nut sleeve. The four keys 7-1502 evenly distributed on the second nut sleeve are installed in cooperation with the grooves 7-1802 evenly distributed in the second arm to prevent the second nut sleeve and the second arm from rotating relative to each other. The threaded holes 7-1503 evenly distributed on the second nut sleeve are installed in cooperation with the through holes 7-1901 on the third arm 7-19. Fig.13 As shown. The second bearing 7-21 is installed on the second shaft section 7-1601 of the second screw 7-16. The six through holes 7-2201 evenly distributed on the third end cover 7-22 are installed in conjunction with the threaded holes 7-1602 evenly distributed on the second screw 7-16 to prevent the second bearing from moving in the axial direction. The fixing ring 7-20 is installed in the radial direction of the second bearing. Its inner wall is matched with the outer diameter of the second bearing, and its outer wall contacts the inner arm of the third arm to play a supporting role. The six threaded holes 7-1902 evenly distributed on the third arm 7-19 are installed in conjunction with the through holes 7-2301 evenly distributed on the connecting piece 7-23, as shown. Fig.15As shown. During operation, the rotor of the motor 7-5 drives the first lead screw 7-9 to rotate. Under the cooperation of the first sleeve and the first arm, the first nut will move along the axis, thereby pushing the part matched by the first nut sleeve to move. At the same time, under the cooperation and installation of the cross section 7-905 of the first lead screw 7-9 and the cross section 7-1603 of the second lead screw 7-16, the second lead screw will perform synchronous rotation with the first lead screw. Similarly, under the cooperation of the second sleeve and the second arm, the second nut will move along the axis, further pushing the third arm to move axially, thereby realizing the synchronous movement of the second arm and the third arm. In order to avoid the entanglement of the cable 7-24 during the movement, a hollow wiring method is adopted, as shown in FIG. Fig.16 shown.

[0064] like Fig.17 As shown, (a) is a space robot with a fixed arm length, (b) is a space robot with the same initial length as (a) but with an arm with telescopic function, the solid line is the boundary of the maximum working space of the space robot, and the area enclosed by the dotted line is the flexible working space of the space robot. The telescopic function of the arm will effectively increase the range of the working space and the flexible working space.

[0065] The above-described embodiments are only preferred specific implementations of the present invention. Common changes and substitutions made by those skilled in the art within the scope of the technical solution of the present invention should be included in the protection scope of the present invention.

Claims

1. A space robot with a reconfigurable working space, characterized in that: It includes a first end effector, a first joint, a first connecting rod, a second joint, a second connecting rod, a third joint, a first telescopic arm, a third connecting rod, a fourth joint, a fourth connecting rod, a second telescopic arm, a fifth joint, a fifth connecting rod, a sixth joint, a sixth connecting rod, a seventh joint and a second end effector connected in sequence; The first end effector is connected to the first connecting rod via a first joint, and the first connecting rod can rotate relative to the first end effector under the drive of the first joint; The first connecting rod and the second connecting rod are connected via a second joint, and the second connecting rod can rotate relative to the first connecting rod under the drive of the second joint; The second connecting rod is connected to the first telescopic arm through a third joint, and the first telescopic arm can rotate relative to the second connecting rod under the drive of the third joint; The first telescopic arm is fixedly connected to the third connecting rod by bolts; the third connecting rod is connected to the fourth connecting rod by a fourth joint, and the fourth connecting rod can rotate relative to the third connecting rod under the drive of the fourth joint; The fourth connecting rod is fixedly connected to the second telescopic arm by bolts; the second telescopic arm is connected to the fifth connecting rod by a fifth joint, and the fifth connecting rod can rotate relative to the second telescopic arm under the drive of the fifth joint; The fifth connecting rod is connected to the sixth connecting rod through a sixth joint, and the sixth connecting rod can rotate relative to the fifth connecting rod under the drive of the sixth joint; The sixth connecting rod is connected to the second end effector via a seventh joint, and the second end effector can rotate relative to the sixth connecting rod under the drive of the seventh joint.

2. The spatial manipulator with reconfigurable working space according to claim 1, characterized in that: The first telescopic arm and the second telescopic arm can both independently perform telescopic movements to change the length of the arm.

3. The spatial manipulator with reconfigurable working space according to claim 1, characterized in that: The first telescopic arm and the second telescopic arm have the same structure, and both include a driver, an encoder, a motor, a support seat, a first nut, a first lead screw, a first nut sleeve, a first end cover, a first bearing, a second nut, a second nut sleeve, a second lead screw, a first arm, a second arm, a third arm, a second bearing and a connecting piece; The first end cover is a hollow boss structure, the bottom surface of which is fixed to the inner flange of the upper end surface of the columnar structure below the support seat; the driver is installed on the bottom surface of the first end cover; The first screw and the second screw are connected in sequence without relative rotation; the two screws have the same structure, both comprising a first shaft section, a second shaft section, and a third shaft section connected in sequence, and the tail end of the third shaft section is a threaded structure; the first bearing is installed on the first shaft section of the second screw, and the second bearing is installed on the second shaft section of the second screw; The first nut is installed in cooperation with the first lead screw, and the second nut is installed in cooperation with the second lead screw. When the first lead screw and the second lead screw rotate, the first nut and the second nut move along the axis of the lead screw. The first arm, the second arm and the third arm are sleeved from outside to inside; the tail end of the third arm is fixedly connected to the connecting piece, and the connecting piece is connected to the third connecting rod; The first nut sleeve is installed on the first nut and is connected to the first arm and the second arm respectively; the second nut sleeve is installed on the second nut and is connected to the second arm and the third arm; The encoder comprises a rotating end and an encoder fixed end, wherein the encoder fixed end is mounted on the protruding surface of the first end cover; the encoder rotating end is fixed to the first shaft end of the first lead screw and rotates synchronously therewith; The support seat is two columnar structures connected up and down, the upper end surface of the lower columnar structure has an inner flange, the upper end surface of the upper columnar structure has an outer flange convex structure, and the upper columnar structure is connected to the third joint; The motor stator is fixedly connected to the inner wall of the cylindrical structure below the support seat, and the rotor is fixedly connected to the second shaft section of the first lead screw.

4. The spatial manipulator with reconfigurable working space according to claim 3, characterized in that: A pair of angular contact bearings is also provided, including a first angular contact bearing and a second angular contact bearing, which are respectively installed on the first shaft section and the third shaft section of the first screw, wherein the first angular contact bearing is axially pressed by the end face of the first end cover and the shoulder of the second shaft section of the first screw, and the second angular contact bearing is axially pressed by the shoulder of the third shaft section of the first screw and the support seat.

5. The spatial robot arm with reconfigurable working space according to claim 3, characterized in that: A fixing nut is also provided, and the fixing nut and the shaft shoulder of the first shaft section of the second lead screw fix the first bearing to prevent the first bearing from moving in the axial direction.

6. The spatial robot arm with reconfigurable working space according to claim 3, characterized in that: A number of through holes are evenly distributed on the first nut, and a groove is provided in the first arm; the first nut sleeve is formed by connecting two upper and lower circular rings of different sizes, and the upper surface of the bottom circular ring is provided with a flange, and the flange is provided with threaded holes, which are installed in conjunction with the corresponding through holes of the first nut; a plurality of evenly distributed keys are provided on the outer periphery of the bottom circular ring, and each key is installed in conjunction with the evenly distributed grooves in the first arm; a threaded hole is provided on the side wall of the circular ring located at the upper part, which is installed in conjunction with the through holes on the second arm.

7. The spatial robot arm with reconfigurable working space according to claim 3, characterized in that: It also includes a fixing ring which is installed in the radial direction of the second bearing. The inner wall of the fixing ring matches the outer diameter of the second bearing. The outer wall of the fixing ring contacts the inner arm of the third arm rod to play a supporting role.

8. The spatial manipulator with reconfigurable working space according to claim 3, characterized in that: A threaded hole is provided on the protruding surface of the first end cover, and a circumferentially arranged threaded hole and through hole are provided on the bottom surface, and the threaded holes on the bottom surface are all located outside the through holes; a through hole is provided on the driver, and the through hole is installed in cooperation with the threaded hole on the bottom surface of the first end cover; a through hole is provided on the fixed end of the encoder, and the through hole is installed in cooperation with the threaded hole on the protruding surface of the first end cover.

9. The spatial robot arm with reconfigurable working space according to claim 3, characterized in that: It also includes a second end cover and a third end cover. The second end cover is fixed to the first nut sleeve, and the third end cover is fixed to the second lead screw.

10. The spatial robot arm with reconfigurable working space according to claim 1, characterized in that: The space robot arm is symmetrically distributed with the fourth joint as the center.

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