Reconfigurable parallel robot for grinding large internal cavity parts with variable diameter

Abstract

The present invention provides a reconfigurable parallel robot for grinding large-scale inner cavity parts with variable diameters, including a first mobile parallel robot and a second reconfigurable parallel robot; the first mobile parallel robot includes: a frame fixed platform, a first moving platform and a plurality of first branches, the bottom of the first branch is installed on the frame fixed platform, and the top of the first branch is rotationally matched with the first moving platform; the second reconfigurable parallel robot includes: a second moving platform, a passive branch and a plurality of second branches, the two ends of the passive branch are respectively connected to the first moving platform and the second moving platform; the bottom of the second branch is installed on the first branch, and the top of the second branch is rotationally matched with the second moving platform. The present invention can output two-turn and one-shift three-degree-of-freedom motion by driving each branch. The change of the terminal output motion is achieved by locking the drive motor or using a limit locking device, which helps to achieve efficient grinding of large inner cavity parts under different inner diameter conditions.

Description

Technical Field

[0001] The invention relates to the field of industrial robots, and in particular to a reconfigurable parallel robot for grinding large inner cavity variable diameter parts. Background Art

[0002] Large internal cavity complex parts are an important part of the core equipment in the fields of aerospace, energy and national defense. They have the characteristics of complex internal cavity shape, poor openness, and difficult to control grinding process. Based on the above characteristics, existing large parts processing equipment, such as traditional multi-axis CNC machine tools and processing robots based on serial robots, cannot be used for internal cavity grinding of large parts due to the limitations of the main body structure or equipment precision / rigidity.

[0003] In view of the above situation, currently, the main method used to grind large inner cavity parts is manual processing, but there are problems such as high labor intensity, low processing efficiency, poor product quality, and difficulty in health protection. Therefore, it is necessary to use appropriate inner cavity parts processing equipment as a replacement. In addition, since some large inner cavity parts have variable diameters, that is, the inner diameter of the parts will change with the increase of depth. Therefore, in order to achieve effective overall grinding, the processing equipment used must also adapt to different inner diameters.

[0004] The existing Chinese patent with publication number CN110682192B discloses a robot grinding equipment and method for the inner cavity of a large container. The equipment includes a robot, a robot linear axis, a workpiece conveyor, a tool library, a rotary table, a workpiece clamping fixture, an end effector, a dust removal device, a grinding room, etc.

[0005] Compared with cantilever chain serial robots, parallel robots are composed of a fixed platform, a moving platform and several motion branches in parallel. They have the advantages of compact structure, high precision and good rigidity, and have been widely used in material sorting and handling, mechanical processing and other fields. By driving the motion branches, traditional parallel robots can only move according to given degrees of freedom, which has certain limitations in application. Different from traditional parallel robots, reconfigurable parallel robots not only retain the inherent advantages of parallel robots, but also can change the terminal output motion by locking the drive motor or using a limit locking device to adapt to different scenarios. Therefore, in view of the current status of grinding processing of large inner cavity parts, it is very necessary to propose a reconfigurable parallel robot for grinding large inner cavity variable diameter parts. Summary of the invention

[0006] In view of the defects in the prior art, the object of the present invention is to provide a reconfigurable parallel robot for grinding large inner cavity variable diameter parts.

[0007] According to the present invention, a reconfigurable parallel robot for grinding large inner cavity variable diameter parts includes a first mobile parallel robot and a second reconfigurable parallel robot; the first mobile parallel robot includes: a frame fixed platform, a first moving platform and multiple first branches, the first branch includes a moving pair and a rotating pair that cooperate with each other, the bottom of the first branch is installed on the frame fixed platform, the top of the first branch is rotationally matched with the first moving platform, and multiple first branches are evenly arranged around the center of the frame fixed platform; the second reconfigurable parallel robot includes: a second moving platform, a passive branch and multiple second branches, the two ends of the passive branch are respectively connected to the first moving platform and the second moving platform; the second branch is arranged corresponding to the first branch, the bottom of the second branch is installed on the first branch, and the top of the second branch is rotationally matched with the second moving platform.

[0008] Preferably, the first branch includes three branches; the first branch includes a first movable pair, a first rotating pair, a first connecting rod and a second rotating pair, the first movable pair is installed on the fixed platform of the frame, the first movable pair is rotationally matched with the first connecting rod through the first rotating pair, and the first connecting rod is rotationally matched with the first movable platform through the second rotating pair.

[0009] Preferably, the first movable pair includes a first movable pair guide rail and a first movable pair slider, the first movable pair slider is installed on the first movable pair guide rail, and the two are slidably matched; the first movable pair guide rail is horizontally arranged on the frame fixed platform, and the first movable pair slider is connected to the first rotating pair and rotates together.

[0010] Preferably, the second branch includes a second movable pair, a first ball joint, a second connecting rod and a second ball joint, the second movable pair is installed on the first connecting rod, the second movable pair is rotationally matched with the second connecting rod through the first ball joint, and the second connecting rod is rotationally matched with the second movable platform through the second ball joint.

[0011] Preferably, the second movable pair includes a second movable pair guide rail and a second movable pair slider, the second movable pair slider is installed on the second movable pair guide rail, and the two are slidingly matched; the second movable pair guide rail is fastened to the first connecting rod, and the second movable pair slider is connected to the first ball joint and rotates together.

[0012] Preferably, the first movable pair and the second movable pair both include a driving pair, and the driving mechanism of the driving pair includes a ball screw mechanism driven by a motor.

[0013] Preferably, the passive branch includes a bearing seat, a Hooke's hinge and a third movable pair, and both ends of the third movable pair are rotatably matched with the bearing seat through the Hooke's hinge, and the two bearing seats are respectively fastened and installed on the top of the first movable platform and the bottom of the second movable platform.

[0014] Preferably, the third movable pair includes a first passive rod and a second passive rod arranged vertically; the Hooke's hinge includes a first Hooke's hinge and a second Hooke's hinge; the first Hooke's hinge includes a first rotating shaft and a second rotating shaft, the first rotating shaft cooperates with the bearing seat to form a rotating pair, and the second rotating shaft is connected to the first passive rod; the second Hooke's hinge includes a first rotating shaft and a second rotating shaft, the first rotating shaft cooperates with the bearing seat to form a rotating pair, and the second rotating shaft is connected to the second passive rod.

[0015] Preferably, the axes of the second rotation axis, the first rotation axis and the third moving pair are arranged perpendicular to each other; the axes of the second rotation axis, the first rotation axis and the third moving pair are arranged perpendicular to each other.

[0016] Preferably, the passive branch further includes a limit locking device, and the limit locking device is used to control the locking or releasing of the second rotating shaft, the first rotating shaft, the second rotating shaft and the first rotating shaft respectively.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] 1. The present invention is formed by connecting a fixed platform, a first moving platform, a second moving platform and a plurality of branches in parallel. By driving each branch, two rotations and one translation can be output to achieve three-degree-of-freedom motion. By locking the drive motor or using a limit locking device to change the output motion at the end, it is helpful to achieve efficient grinding of large inner cavity parts with different inner diameters.

[0019] 2. The present invention can move according to given degrees of freedom through the coordinated use of multiple drive pairs and multiple limit locking devices. It can also adapt to different scenarios and different inner diameter conditions, achieve different three-degree-of-freedom motion outputs and complete grinding, which helps to improve the scope of application.

[0020] 3. The present invention connects various platforms through the first branch, the second branch and the passive branch, and has a compact structure, high precision, good rigidity and strong load capacity, which helps to improve environmental adaptability and helps to achieve efficient grinding of large inner cavity parts under different inner diameters. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Other features, objects and advantages of the present invention will become more apparent from the detailed description of non-limiting embodiments made with reference to the following drawings:

[0022] Figure 1 This is a schematic diagram of the overall structure of a reconfigurable parallel robot used for grinding large internal cavity parts with variable diameters;

[0023] Figure 2 This is a schematic diagram of the three-dimensional structure of a first mobile parallel robot mainly embodied in the present invention;

[0024] Figure 3 It is a schematic diagram of the three-dimensional structure of the second reconfigurable parallel robot mainly embodied in the present invention;

[0025] Figure 4 This is a schematic diagram of the three-dimensional structure of the present invention mainly embodies the grinding of large inner cavity type variable diameter parts;

[0026] Figure 5 This is a schematic diagram of the three-dimensional structure of the first branch of the present invention;

[0027] Figure 6 This is a schematic diagram of the three-dimensional structure of the second branch of the present invention;

[0028] Figure 7 It is a schematic diagram of the three-dimensional structure of the passive branch mainly embodied in the present invention.

[0029] As shown in the figure:

[0030] Frame fixed platform 1 First moving auxiliary guide rail 11

[0031] First moving pair slider 12 First rotating pair 13

[0032] First connecting rod 14 Second rotating pair 15

[0033] First moving platform 2 Second moving auxiliary guide rail 21

[0034] Second movable auxiliary slider 22 First ball joint 23

[0035] Second connecting rod 24 Second ball joint 25

[0036] Second moving platform 3 First bearing seat 31

[0037] Second bearing seat 32 Third bearing seat 33

[0038] Fourth bearing seat 34 First limit locking device 35

[0039] The first small limit motor 351 The first active limit rod 352

[0040] First limiting ring 353 Second limiting locking device 36

[0041] Second small limit motor 361 Second active limit rod 362

[0042] Second limiting ring 363 Third limiting locking device 37

[0043] The third small limiting motor 371 The third active limiting rod 372

[0044] The third limiting ring 373 The fourth limiting locking device 38

[0045] Fourth small limit motor 381 Fourth active limit rod 382

[0046] Fourth limiting ring 383 First Hooke hinge 39

[0047] Second Hooke's hinge 310 First passive rod 311

[0048] The second passive rod 312 The first rotation axis 313

[0049] Second rotation axis 314 First rotation axis 315

[0050] Second rotating shaft 316 Inner cavity type variable diameter part 4 DETAILED DESCRIPTION

[0051] The present invention is described in detail below in conjunction with specific embodiments. The following embodiments will help those skilled in the art to further understand the present invention, but are not intended to limit the present invention in any form. It should be noted that, for those of ordinary skill in the art, several changes and improvements can also be made without departing from the concept of the present invention. These all belong to the protection scope of the present invention.

[0052] like Figure 1-4 As shown, a reconfigurable parallel robot for grinding large inner cavity variable diameter parts provided according to the present invention includes a first mobile parallel robot and a second reconfigurable parallel robot; the first mobile parallel robot includes: a frame fixed platform 1, a first moving platform 2 and multiple first branches, the first branch includes a moving pair and a rotating pair that cooperate with each other, the bottom of the first branch is installed on the frame fixed platform 1, the top of the first branch is rotationally matched with the first moving platform 2, and the multiple first branches are evenly arranged around the center of the frame fixed platform 1; the second reconfigurable parallel robot includes: a second moving platform 3, a passive branch and multiple second branches, the two ends of the passive branch are respectively connected to the first moving platform 2 and the second moving platform 3; the second branch is arranged corresponding to the first branch, the bottom of the second branch is installed on the first branch, and the top of the second branch is rotationally matched with the second moving platform 3.

[0053] The present application can achieve different three-degree-of-freedom motion outputs by installing the second reconfigurable parallel robot on the first mobile parallel robot, and can be used for the grinding processing of large inner cavity variable diameter parts 4. It has the advantages of high precision / rigidity, strong load-bearing capacity, and strong adaptability to inner diameter changes. It can achieve efficient grinding of large inner cavity parts under different inner diameter conditions.

[0054] like Figure 5 As shown, the first branch includes three branches; the first branch includes a first movable pair, a first rotating pair 13, a first connecting rod 14 and a second rotating pair 15. The first movable pair is installed on the frame fixed platform 1, and the first movable pair is rotationally matched with the first connecting rod 14 through the first rotating pair 13. The first connecting rod 14 is rotationally matched with the first movable platform 2 through the second rotating pair 15.

[0055] The first movable pair includes a first movable pair guide rail 11 and a first movable pair slider 12. The first movable pair slider 12 is installed on the first movable pair guide rail 11, and the two are slidably matched; the first movable pair guide rail 11 is horizontally arranged on the frame fixed platform 1, and the first movable pair slider 12 is connected to the first rotating pair 13 and rotates together.

[0056] The first moving pair is a driving pair. The driving mechanism of the first moving pair is a ball screw mechanism driven by a motor. Through the driving motor, the first mobile parallel robot can achieve movement perpendicular to the horizontal plane, completing the second reconfigurable parallel robot entering / exiting the inner cavity of a large part.

[0057] like Figure 6 As shown, the second branch includes a second movable pair, a first ball joint 23, a second connecting rod 24 and a second ball joint 25. The second movable pair is installed on the first connecting rod 14. The second movable pair is rotationally matched with the second connecting rod 24 through the first ball joint 23, and the second connecting rod 24 is rotationally matched with the second movable platform 3 through the second ball joint 25.

[0058] The second movable pair includes a second movable pair guide rail 21 and a second movable pair slider 22. The second movable pair slider 22 is installed on the second movable pair guide rail 21, and the two are slidably matched; the second movable pair guide rail 21 is fastened to the first connecting rod 14, and the second movable pair slider 22 is connected to the first ball joint 23 and rotates together.

[0059] like Figure 7 As shown, the passive branch includes a bearing seat, a Hooke's hinge and a third moving pair, and the two ends of the third moving pair are respectively rotatably matched with the bearing seat through the Hooke's hinge, and the two bearing seats are respectively fastened and installed on the top of the first moving platform 2 and the bottom of the second moving platform 3. The bearing seat includes a first bearing seat 31, a second bearing seat 32, a third bearing seat 33 and a fourth bearing seat 34.

[0060] The third moving pair includes a first passive rod 311 and a second passive rod 312 which are arranged vertically. The first passive rod 311 cooperates with the second passive rod 312 to form the third moving pair. The Hooke's hinge includes a first Hooke's hinge 39 and a second Hooke's hinge 310. The first Hooke's hinge 39 includes a first rotating shaft 313 and a second rotating shaft 314. The first rotating shaft 313 cooperates with a bearing seat to form a rotating pair. The first rotating shaft 313 cooperates with a first bearing seat 31 and a second bearing seat 32 installed on the first moving platform 2 to form a rotating pair; the second rotating shaft 314 is connected to the first passive rod 311. The axes of the second rotating shaft 314, the first rotating shaft 313 and the third moving pair are arranged perpendicular to each other.

[0061] The second Hooke's joint 310 includes a first rotating shaft 315 and a second rotating shaft 316. The first rotating shaft 315 cooperates with the bearing seat to form a rotating pair. The first rotating shaft 315 cooperates with the third bearing seat 33 and the fourth bearing seat 34 installed on the second moving platform 2 to form a rotating pair. The second rotating shaft 316 is connected to the second passive rod 312. The axes of the second rotating shaft 316, the first rotating shaft 315 and the third moving pair are arranged perpendicular to each other.

[0062] The passive branch also includes a limit locking device, which is used to respectively control the locking or release of the second rotating shaft 314, the first rotating shaft 313, the second rotating shaft 316, and the first rotating shaft 315. The limit locking device includes a first limit locking device 35, a second limit locking device 36, a third limit locking device 37, and a fourth limit locking device 38.

[0063] The first limit locking device 35 includes a first small limit motor 351, a first active limit rod 352 and a first limit ring 353; the first small limit motor 351 is fixedly connected to the side of the second bearing seat 32; the first limit ring 353 is fixedly connected to the first rotating shaft 313, and the center axis coincides with the axis of the first rotating shaft 313; the first active limit rod 352 is connected to the first small limit motor 351, and can move up and down by driving the first small limit motor 351 to achieve locking or releasing of the first rotating shaft 313.

[0064] The second limit locking device 36 includes a second small limit motor 361, a second active limit rod 362 and a second limit ring 363; the second small limit motor 361 is fixedly connected to the side of the first passive rod 311; the second limit ring 363 is fixedly connected to the second rotating shaft 314, and the center axis coincides with the axis of the second rotating shaft 314; the second active limit rod 362 is connected to the second small limit motor 361, and can move up and down by driving the second small limit motor 361 to achieve locking or releasing of the second rotating shaft 314.

[0065] The third limit locking device 37 includes a third small limit motor 371, a third active limit rod 372 and a third limit ring 373; the third small limit motor 371 is fixedly connected to the side of the second passive rod 312; the third limit ring 373 is fixedly connected to the second rotating shaft 316, and the center axis coincides with the axis of the second rotating shaft 316; the third active limit rod 372 is connected to the third small limit motor 371, and can move up and down by driving the third small limit motor 371 to achieve locking or release of the second rotating shaft 316.

[0066] The fourth limit locking device 38 includes a fourth small limit motor 381, a fourth active limit rod 382 and a fourth limit ring 383; the fourth small limit motor 381 is fixedly connected to the side of the fourth bearing seat 34; the fourth limit ring 383 is fixedly connected to the first rotating shaft 315, and the center axis coincides with the axis of the first rotating shaft 315; the fourth active limit rod 382 is connected to the fourth small limit motor 381, and can move up and down by driving the fourth small limit motor 381 to achieve locking or release of the first rotating shaft 315.

[0067] The second moving pair includes a driving pair, and the driving mechanism of the driving pair includes a ball screw mechanism driven by a motor. The third moving pair is a passive pair.

[0068] When the driving pair moves, the first limit locking device 35 and the second limit locking device 36 respectively lock the first rotation axis 313 and the second rotation axis 314 of the first Hooke's joint 39, and the parallel robot can output two rotations and one translation three-degree-of-freedom motion, which are respectively rotation around the axis of the first rotation axis 315 of the second Hooke's joint 310, rotation around the axis of the second rotation axis 316 of the second Hooke's joint 310, and movement along the third moving pair. When the driving pair moves, the first limit locking device 35 and the third limit locking device 37 respectively lock the first rotation axis 313 of the first Hooke's joint 39 and the second rotation axis 316 of the second Hooke's joint 310, and the parallel robot can output two rotations and one translation three-degree-of-freedom motion, which are respectively rotation around the axis of the second rotation axis 314 of the first Hooke's joint 39, rotation around the axis of the first rotation axis 315 of the second Hooke's joint 310, and movement along the third moving pair. When the driving pair moves, the second limit locking device 36 and the fourth limit locking device 38 respectively lock the second rotation axis 314 of the first Hooke's joint 39 and the first rotation axis 315 of the second Hooke's joint 310, and the parallel robot can output two rotations and one translation three-degree-of-freedom motion, which are respectively rotation around the axis of the first rotation axis 313 of the first Hooke's joint 39, rotation around the axis of the second rotation axis 316 of the second Hooke's joint 310, and movement along the third moving pair. When the driving pair moves, the third limit locking device 37 and the fourth limit locking device 38 respectively lock the first rotation axis 315 and the second rotation axis 316 of the second Hooke's joint 310, and the parallel robot can output two rotations and one translation three-degree-of-freedom motion, which are respectively rotation around the axis of the first rotation axis 313 of the first Hooke's joint 39, rotation around the axis of the second rotation axis 314 of the first Hooke's joint 39, and movement along the third moving pair.

[0069] In response to changes in the inner diameter, the terminal output freedom can be adjusted through the above-mentioned limit locking device.

[0070] The present application is formed by a frame fixed platform 1, a first moving platform 2, a second moving platform 3 and a plurality of branches connected in parallel, and has the advantages of compact structure, high precision, good rigidity, etc., and can be widely used in the fields of material sorting and handling, mechanical processing, etc. The present application can move according to a given degree of freedom by driving each branch, and can also change the terminal output motion by locking the drive motor or using a limit locking device to adapt to different scenarios. The present application can achieve different three-degree-of-freedom motion outputs and complete grinding according to the different inner diameters of the inner cavity type variable diameter parts 4, and has the advantages of good environmental adaptability, etc.

[0071] How it works

[0072] When the driving pair moves, the first limit locking device 35 and the second limit locking device 36 respectively lock the first rotation axis 313 and the second rotation axis 314 of the first Hooke's joint 39, and the parallel robot can output two rotations and one translation three-degree-of-freedom motion, which are respectively rotation around the axis of the first rotation axis 315 of the second Hooke's joint 310, rotation around the axis of the second rotation axis 316 of the second Hooke's joint 310, and movement along the third moving pair. When the driving pair moves, the first limit locking device 35 and the third limit locking device 37 respectively lock the first rotation axis 313 of the first Hooke's joint 39 and the second rotation axis 316 of the second Hooke's joint 310, and the parallel robot can output two rotations and one translation three-degree-of-freedom motion, which are respectively rotation around the axis of the second rotation axis 314 of the first Hooke's joint 39, rotation around the axis of the first rotation axis 315 of the second Hooke's joint 310, and movement along the third moving pair. When the driving pair moves, the second limit locking device 36 and the fourth limit locking device 38 respectively lock the second rotation axis 314 of the first Hooke's joint 39 and the first rotation axis 315 of the second Hooke's joint 310, and the parallel robot can output two rotations and one translation three-degree-of-freedom motion, which are respectively rotation around the axis of the first rotation axis 313 of the first Hooke's joint 39, rotation around the axis of the second rotation axis 316 of the second Hooke's joint 310, and movement along the third moving pair. When the driving pair moves, the third limit locking device 37 and the fourth limit locking device 38 respectively lock the first rotation axis 315 and the second rotation axis 316 of the second Hooke's joint 310, and the parallel robot can output two rotations and one translation three-degree-of-freedom motion, which are respectively rotation around the axis of the first rotation axis 313 of the first Hooke's joint 39, rotation around the axis of the second rotation axis 314 of the first Hooke's joint 39, and movement along the third moving pair.

[0073] In the description of the present application, it should be understood that the terms "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0074] The above describes the specific embodiments of the present invention. It should be understood that the present invention is not limited to the above specific embodiments, and those skilled in the art can make various changes or modifications within the scope of the claims, which does not affect the essence of the present invention. In the absence of conflict, the embodiments of the present application and the features in the embodiments can be combined with each other arbitrarily.

Claims

1. A reconfigurable parallel robot for grinding large internal cavity parts with variable diameter, characterized in that: It includes a first mobile parallel robot and a second reconfigurable parallel robot; The first mobile parallel robot comprises: a frame fixed platform (1), a first moving platform (2) and a plurality of first branches, wherein the first branch comprises a moving pair and a rotating pair that cooperate with each other, the bottom of the first branch is mounted on the frame fixed platform (1), the top of the first branch is rotationally matched with the first moving platform (2), and the plurality of first branches are evenly arranged around the center of the frame fixed platform (1); The second reconfigurable parallel robot comprises: a second moving platform (3), a passive branch and a plurality of second branches, wherein two ends of the passive branch are respectively connected to the first moving platform (2) and the second moving platform (3); The second branch is arranged corresponding to the first branch, the bottom of the second branch is mounted on the first branch, and the top of the second branch is rotatably matched with the second moving platform (3); The passive branch comprises a bearing seat, a Hooke's hinge and a third movable pair, the two ends of the third movable pair are respectively rotatably matched with the bearing seat through the Hooke's hinge, and the two bearing seats are respectively fastened and installed on the top of the first movable platform (2) and the bottom of the second movable platform (3); The third movable pair comprises a first passive rod (311) and a second passive rod (312) which are vertically arranged; The Hooke's hinge comprises a first Hooke's hinge (39) and a second Hooke's hinge (310); The first Hooke's hinge (39) comprises a first rotating shaft (313) and a second rotating shaft (314), the first rotating shaft (313) cooperates with the bearing seat to form a rotating pair, and the second rotating shaft (314) is connected to the first passive rod (311); The second Hooke's hinge (310) comprises a first rotating shaft (315) and a second rotating shaft (316), wherein the first rotating shaft (315) cooperates with the bearing seat to form a rotating pair, and the second rotating shaft (316) is connected to the second passive rod (312); The passive branch further comprises a limit locking device, wherein the limit locking device is used to respectively control the locking or releasing of the second rotating shaft (314), the first rotating shaft (313), the second rotating shaft (316) and the first rotating shaft (315); The position limiting locking device includes a first position limiting locking device, a second position limiting locking device, a third position limiting locking device and a fourth position limiting locking device; The first limit locking device includes a first small limit motor, a first active limit rod and a first limit ring; the first small limit motor is fixedly connected to the side of the second bearing seat; the first limit ring is fixedly connected to the first rotating shaft, and the central axis coincides with the axis of the first rotating shaft; the first active limit rod is connected to the first small limit motor, and can move up and down by driving the first small limit motor to achieve locking or releasing of the first rotating shaft (313).

2. The reconfigurable parallel robot for grinding large internal cavity variable diameter parts according to claim 1, characterized in that: The first branch includes three branches; The first branch comprises a first movable pair, a first rotating pair (13), a first connecting rod (14) and a second rotating pair (15); the first movable pair is mounted on the frame fixed platform (1); the first movable pair is rotationally matched with the first connecting rod (14) via the first rotating pair (13); the first connecting rod (14) is rotationally matched with the first movable platform (2) via the second rotating pair (15).

3. The reconfigurable parallel robot for grinding large internal cavity variable diameter parts according to claim 2, characterized in that: The first moving pair comprises a first moving pair guide rail (11) and a first moving pair slider (12), wherein the first moving pair slider (12) is mounted on the first moving pair guide rail (11), and the two are slidably matched; The first movable pair guide rail (11) is horizontally arranged on the frame fixed platform (1), and the first movable pair slide block (12) is connected to the first rotating pair (13) and is rotationally matched.

4. The reconfigurable parallel robot for grinding large internal cavity variable diameter parts according to claim 2, characterized in that: The second branch includes a second movable pair, a first ball joint (23), a second connecting rod (24) and a second ball joint (25); the second movable pair is mounted on the first connecting rod (14); the second movable pair is rotationally engaged with the second connecting rod (24) via the first ball joint (23); the second connecting rod (24) is rotationally engaged with the second movable platform (3) via the second ball joint (25).

5. The reconfigurable parallel robot for grinding large internal cavity variable diameter parts according to claim 4, characterized in that: The second moving pair comprises a second moving pair guide rail (21) and a second moving pair slider (22), wherein the second moving pair slider (22) is mounted on the second moving pair guide rail (21), and the two are slidably matched; The second movable auxiliary guide rail (21) is fixedly mounted on the first connecting rod (14), and the second movable auxiliary sliding block (22) is connected to the first ball joint (23) and is rotationally matched.

6. The reconfigurable parallel robot for grinding large internal cavity variable diameter parts according to claim 4, characterized in that: The first moving pair and the second moving pair both include a driving pair, and the driving mechanism of the driving pair includes a ball screw mechanism driven by a motor.

7. The reconfigurable parallel robot for grinding large internal cavity variable diameter parts according to claim 1, characterized in that: The axes of the second rotating shaft (314), the first rotating shaft (313) and the third moving pair are arranged perpendicular to each other; The axes of the second rotating shaft (316), the first rotating shaft (315) and the third moving pair are arranged perpendicular to each other.

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