Motion redundancy five-degree-of-freedom series-parallel processing robot with symmetrical structure

Abstract

The invention relates to the technical field of robots, in particular to a motion redundancy five-degree-of-freedom series-parallel machining robot with a symmetrical structure, which comprises a base, a stand column, a rack, a movable platform, a cutter, a workbench, an X / Y-axis sliding table and three parallel branches, two side branches with the same structure are symmetrically arranged, the upper end of a middle branch is connected with the rack through a moving pair, and the lower end of the middle branch is connected with the rack through a moving pair; the lower end of each side branch adopts a rotating pair, the lower end of each middle branch adopts a hooke joint, a cutter is installed on an electric spindle of the movable platform, a workbench is installed on an X-axis sliding table through a rotating pair, the sliding tables are combined to achieve rotation of the workbench around the X axis and movement in the X-Y plane, and the six active driving pairs are controlled in a coordinated mode to drive the workbench to rotate around the X axis and move in the X-Y plane. By introducing the motion redundancy design, singular configurations are effectively reduced, the posture rotation capacity is improved, and the multi-axis multi-degree-of-freedom parallel mechanism is particularly suitable for high-speed and high-precision machining of complex parts.

Description

Technical Field

[0001] This invention relates to the field of robotics, specifically to a structurally symmetrical, motion-redundant, five-degree-of-freedom hybrid machining robot. Background Technology

[0002] Serial robots offer a large workspace, independent operation of each axis, high flexibility, and simple motion control, thus compensating for the shortcomings of traditional machining to a certain extent. They significantly improve the surface finish, flatness, and machining efficiency of complex parts compared to traditional methods. Compared to serial robots, parallel robots have significant advantages in stiffness, precision, speed, and dynamic performance, and are therefore widely used in industrial production, such as in material handling and palletizing, motion simulation, surgical procedures, and parts processing.

[0003] To overcome the shortcomings of serial and parallel machining, hybrid machining robots have emerged, capable of high-speed machining of complex parts within a larger workspace, representing a development direction for five-axis linkage machining robots. Hybrid robots combine the main advantages of both parallel and serial robots, possessing numerous advantages such as high rigidity, high speed, strong load-bearing capacity, and low cost, leading the development of efficient, high-speed, and high-precision CNC machining equipment. However, from a mechanistic perspective, existing hybrid machining robot configurations still cannot meet the demands for efficient machining of complex parts. The main reasons are: existing core modules of hybrid machining robots, such as the Z3 spindle head (3-PRS parallel mechanism) and the 2UPR-RPU parallel mechanism, lack redundant degrees of freedom, have numerous singular configurations, and weak rotational capabilities, making it difficult to adapt to the large-area rotational workspace requirements of complex part machining; currently, the core modules of hybrid machining robots widely used in the market, such as the Z3 parallel spindle head, are protected by patents abroad. Therefore, there is an urgent need to design a structurally symmetrical, motion-redundant, five-degree-of-freedom hybrid machining robot. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the present invention aims to provide a structurally symmetrical, motion-redundant, five-degree-of-freedom hybrid machining robot.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a symmetrically structured, motion-redundant, five-degree-of-freedom hybrid machining robot, comprising a base (10), a column, a frame, two symmetrically arranged side branches, a middle branch, a moving platform, a cutting tool, a worktable, an X-axis slide, and a Y-axis slide; The base (10) is fixed to the ground, the column is vertically installed on the base (10), and the frame is installed on the column; The upper ends of the two side branches and one middle branch are connected to the frame via sliding joints; the lower ends of the two side branches are connected to the moving platform via revolute joints; the lower end of the middle branch is connected to the moving platform via a Hooke joint; the cutting tool is mounted on the electric spindle, and the electric spindle is fixed at the center of the moving platform. The worktable is connected to the X-axis slide via a rotary joint, the X-axis slide is connected to the Y-axis slide via a guide rail, and the Y-axis slide is connected to the base (10) via a guide rail; The moving platform has a degree of freedom to rotate about the Y-axis and a degree of freedom to move along the Z-axis; the worktable has a degree of freedom to rotate about the X-axis; the X-axis slide has a degree of freedom to move along the X-axis; and the Y-axis slide has a degree of freedom to move along the Y-axis. The robot achieves five-degree-of-freedom motion and motion redundancy control through six drive pairs, which are distributed on the side branches and the middle branch.

[0006] In some embodiments, the movable sub-axis connecting the upper ends of the side branches and the middle branches to the frame is at the same height and arranged horizontally. The axis of the rotating joint connecting the lower end of the side branch to the moving platform is parallel to each other and perpendicular to the X-direction axis of the Hooke pair of the middle branch; The rotational subcenters of the two lateral branches and the Hooke subcenter of the middle branch form an isosceles right triangle.

[0007] In some embodiments, the side branch is a PRPR branch, comprising a sliding joint (P), a revolute joint (R), a sliding joint (P), and a revolute joint (R) connected in sequence, with the following structure: The sliding pair slider and the frame guide rail form the first sliding pair; The slider and the through hole of the telescopic outer rod cooperate to form the first rotating pair; The telescopic outer rod and the telescopic inner rod form a second sliding joint; The end of the telescopic inner rod is connected to the moving platform via a second revolute joint.

[0008] In some embodiments, the intermediate branch is a PRPU branch, comprising a sliding joint (P), a revolute joint (R), a sliding joint (P), and a Hooke's joint (U) connected in sequence, with the following structure: The sliding pair slider and the frame guide rail form a third sliding pair; The slider and the through hole of the telescopic outer rod cooperate to form a third rotating pair; The telescopic outer rod and the telescopic inner rod form a fourth sliding joint; The end of the telescopic inner rod is connected to the moving platform via a Hooke hinge, and the first axis of the Hooke hinge is parallel to the axis of the third rotating pair.

[0009] In some embodiments, the intermediate branch is a PRRU branch, comprising a prismatic joint (P), a revolute joint (R), a revolute joint (R), and a Hooke's joint (U) connected in sequence, with the following structure: The sliding pair slider and the frame guide rail form a fourth sliding pair; The slider and the through hole of the connecting rod form a fourth rotating pair; The middle connecting rod and the outer connecting rod through the through hole form the fifth rotating pair; The end of the outer connecting rod is connected to the moving platform via a Hooke joint, and the first axis of the Hooke joint is parallel to the axis of the fifth revolute joint.

[0010] In some embodiments, the side branch is a PRRR branch, comprising a sliding joint (P), a revolute joint (R), a revolute joint (R), and a revolute joint (R) connected in sequence, with the following structure: The sliding block of the movable pair forms a second movable pair with the frame guide rail; The slider and the through hole of the connecting rod form the seventh rotating pair; The middle connecting rod and the outer connecting rod through the hole form the eighth rotating pair; The end of the outer connecting rod is connected to the moving platform via the sixth revolute joint.

[0011] In some embodiments, the intermediate branch is a PRPU branch, comprising a sliding joint (P), a revolute joint (R), a sliding joint (P), and a Hooke's joint (U) connected in sequence, with the following structure: The sliding pair slider and the frame guide rail form a third sliding pair; The slider and the external connecting rod through hole cooperate to form the ninth rotating pair; The outer link and the inner link form the fifth sliding joint; The end of the inner connecting rod is connected to the moving platform via a Hooke joint, and the first axis of the Hooke joint is parallel to the axis of the ninth rotating joint.

[0012] In some embodiments, the intermediate branch is a PRRU branch, comprising a prismatic joint (P), a revolute joint (R), a revolute joint (R), and a Hooke's joint (U) connected in sequence, with the following structure: The sliding pair slider and the frame guide rail form a fourth sliding pair; The slider and the through hole of the connecting rod form a fourth rotating pair; The middle connecting rod and the outer connecting rod through the through hole form the fifth rotating pair; The end of the outer connecting rod is connected to the moving platform via a Hooke joint, and the first axis of the Hooke joint is parallel to the axis of the fifth revolute joint.

[0013] In some embodiments, the worktable, the X-axis slide, and the Y-axis slide constitute a series motion chain, the structure of which is as follows: The worktable is connected to the X-axis slide via a rotary joint, enabling it to rotate around the X-axis; The X-axis slide is connected to the Y-axis slide via a guide rail pair to achieve X-axis movement; The Y-axis slide is connected to the base via a guide rail pair, enabling movement in the Y direction.

[0014] In some embodiments, the six drive pairs are selected from one of the following combinations: (a) Four moving parts of two PRPR branches + two moving parts of the PRPU branch; (b) Four moving joints of two PRPR branches + one moving joint and one revolute joint (fifth revolute joint) of the PRRU branch. (c) Two prismatic joints and two revolute joints (seventh revolute joint) of the two PRRR branches + two prismatic joints of the PRPU branch; (d) Two translating joints and two revolute joints (seventh revolute joint) of two PRRR branches + one translating joint and one revolute joint (fifth revolute joint) of the PRRU branch.

[0015] Compared with existing technologies, the beneficial effects of this invention are: combining the advantages of serial and parallel robots, and through in-depth research on five-degree-of-freedom hybrid machining robots, the motion-redundant hybrid machining robot proposed in this invention possesses motion redundancy characteristics, resulting in high machining speed and precision, a large workspace, and high flexibility. This hybrid robot has significant advantages in machining complex parts with large cutting volumes, overcoming the shortcomings of serial and parallel robots, and enabling high-speed machining of complex parts within a large workspace.

[0016] Details of one or more embodiments of this application are set forth in the following drawings and description to make other features, objects and advantages of this application more readily apparent. The embodiments of this application will provide a detailed description and understanding of the application. Attached Figure Description

[0017] Figure 1 This is a three-dimensional structural diagram of Embodiment 1 of the present invention; Figure 2 This is a three-dimensional structural diagram of Embodiment 2 of the present invention; Figure 3 This is a three-dimensional structural diagram of Embodiment 3 of the present invention; Figure 4 This is a three-dimensional structural diagram of Embodiment 4 of the present invention; Figure 5 This is a schematic diagram of the three-dimensional structure of the first branch; Figure 6 This is a schematic diagram of the three-dimensional structure of the second branch; Figure 7 This is a schematic diagram of the three-dimensional structure of the third branch; Figure 8This is a schematic diagram of the three-dimensional structure of the fourth branch; Figure 9 This is a schematic diagram of the three-dimensional structure of the slide and the worktable.

[0018] In the diagram: 1. Column; 2. Frame; 3. Side branch; 4. Middle branch; 5. Moving platform; 6. Tool; 7. Worktable; 8. X-axis slide; 9. Y-axis slide; 10. Base; 11. First movable auxiliary slider; 12. Telescopic outer rod; 13. Telescopic inner rod; 21. Moving auxiliary slider; 22. Middle connecting rod; 23. Outer connecting rod; 31. Moving auxiliary slider; 32. Telescopic outer rod; 33. Telescopic inner rod; 34. Hooke's hinge; 41. Moving auxiliary slider; 42. Middle connecting rod; 43. Outer connecting rod; 44. Hooke's joint; 51. Rotary joint; 52. Guide rail joint; 53. Guide rail joint. Detailed Implementation

[0019] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] This invention provides a technical solution: a symmetrical, motion-redundant, five-degree-of-freedom hybrid machining robot, with a general structure in various embodiments as follows: Figure 1-4 As shown, all embodiments include the following basic components: Includes base (10), column (1), frame (2), two symmetrically arranged side branches (3), one middle branch (4), moving platform (5), cutting tool (6), worktable (7), X-axis slide (8), Y-axis slide (9); The base (10) is fixed to the ground, the column (1) is vertically installed on the base (10), and the frame (2) is installed on the column (1); The upper ends of the two side branches (3) and one middle branch (4) are connected to the frame (2) through a sliding joint; the lower ends of the two side branches (3) are connected to the moving platform (5) through a rotating joint; the lower end of the middle branch (4) is connected to the moving platform (5) through a Hooke joint; the cutting tool (6) is mounted on the electric spindle, and the electric spindle is fixed at the center of the moving platform (5); The worktable (7) is connected to the X-axis slide (8) via a rotating joint. The X-axis slide (8) is connected to the Y-axis slide (9) via a guide rail. The Y-axis slide (9) is connected to the base (10) via a guide rail. The moving platform (5) has a degree of freedom to rotate about the Y-axis and a degree of freedom to move along the Z-axis. The worktable (7) has a degree of freedom to rotate about the X-axis. The X-axis slide (8) has a degree of freedom to move along the X-axis. The Y-axis slide (9) has a degree of freedom to move along the Y-axis. The robot achieves five-degree-of-freedom motion and motion redundancy control through six drive pairs, which are distributed on the side branch (3) and the middle branch (4).

[0021] In the specific implementation process of the above technical solution: Example

[0022] like Figure 1 , 5 As shown in Figures 7 and 9, this embodiment adopts a configuration of two PRPR side branches + one PRPU middle branch: 1. Branching structure (a) Side branch (first branch / PRPR type): First moving pair: The sliding block (11) of the moving pair cooperates with the upper guide rail of the frame (2). First rotating joint: The slider (11) and the telescopic outer rod (12) are fitted with a through hole (horizontal axis). Second sliding joint: sleeve fit between the telescopic outer rod (12) and the telescopic inner rod (13) Second revolute joint: The end of the telescopic inner rod (13) is connected to the moving platform (5) (the axis is parallel to the first revolute joint). (b) Intermediate branch (third branch / PRPU type): Third moving pair: The sliding block (31) of the moving pair cooperates with the upper guide rail of the frame (2). Third rotating joint: The slider (31) and the telescopic outer rod (32) are fitted with a through hole (vertical axis). Fourth sliding joint: Sleeve fit between the telescopic outer rod (32) and the telescopic inner rod (33) Hooke hinge (34): The end of the telescopic inner rod (33) is connected to the moving platform (5), and its first rotating shaft is parallel to the axis of the third rotating joint; 2. Drive system 6 drive pairs: ①-②: The first and second moving parts of the left PRPR branch ③-④: The first and second moving joints of the right-hand PRPR branch ⑤: The third moving sub-part of the PRPU branch ⑥: The fourth moving sub-sub in the PRPU branch Execution method: Servo motor drives ball screw (not shown in the figure); 3. Geometric Constraints The first movable pair slider 11 cooperates with the first movable pair guide rail fixed on the frame to form a first movable pair. The first movable pair slider 11 cooperates with the through hole of the first telescopic outer rod 12 to form a first rotating pair. The first telescopic inner rod 13 cooperates with the first telescopic outer rod to form a second movable pair. The axis of the first rotating pair is perpendicular to the axes of the first and second rotating pairs. The third sliding pair slider 31 cooperates with the third sliding pair guide rail fixed on the frame to form the third sliding pair. The third sliding pair slider 31 cooperates with the through hole of the third telescopic outer rod 32 to form the third rotating pair. The third telescopic inner rod 33 cooperates with the third telescopic outer rod to form the second sliding pair.

[0023] The first rotating shaft axis connecting the third Hooke hinge 34 and the inner rod of the third telescopic rod 33 is parallel to the axis of the third rotating joint and perpendicular to the axis of the second sliding joint. In the two first branches, the axes of the two first prismatic joints coincide, and the axes of the two first and second revolute joints are parallel; The second rotation axis of the third Hooke's hinge in the third branch is parallel to the axis of the first rotational joint in the first branch. 4. Motion redundancy implementation The drive pairs are the sliding pairs on each branch, and the drive method can be either ball screw or hydraulic drive. From the beginning, by controlling the movement of the six drive pairs, the three branches of the mechanism can generate redundant degrees of freedom, reduce the input singular configuration, increase the rotation angle of the moving platform, and improve the flexibility of the mechanism. Example

[0024] like Figure 2 , 5 As shown in Figures 8 and 9, this embodiment adopts a configuration of two PRPR side branches + one PRRU middle branch: 1. Branching structure (a) Side branch (same as PRPR type in Example 1): The structural configuration is exactly the same as in Example 1. (b) Intermediate branch (fourth branch / PRRU type): Fourth moving pair: The sliding block (41) of the moving pair cooperates with the upper guide rail of the frame (2). Fourth rotating joint: The slider (41) and the connecting rod (42) are fitted through the hole (vertical axis). Fifth rotating joint: Through-hole fit between the middle connecting rod (42) and the outer connecting rod (43) (horizontal axis) Hooke hinge (44): The end of the outer connecting rod (43) is connected to the moving platform (5), and its first rotating axis is parallel to the axis of the fifth rotating joint. 2. Drive system 6 drive pairs: ①-④: Four moving pairs of the two PRPR branches (same as in Example 1) ⑤: The fourth moving sub-branch of the PRRU branch ⑥: The fifth rotary joint of the PRRU branch (driven by a rotary servo motor) 3. Geometric Constraints The first movable pair slider 11 cooperates with the first movable pair guide rail fixed on the frame to form a first movable pair. The first movable pair slider 11 cooperates with the through hole of the first telescopic outer rod 12 to form a first rotating pair. The first telescopic inner rod 13 cooperates with the first telescopic outer rod to form a second movable pair. The axis of the first rotating pair is perpendicular to the axes of the first and second rotating pairs. The fourth sliding pair slider 41 cooperates with the third sliding pair guide rail fixed on the frame to form the fourth sliding pair. The fourth sliding pair slider 41 cooperates with the through hole of the fourth middle connecting rod 42 to form the fourth rotating pair. The fourth outer connecting rod 43 cooperates with the through hole of the fourth middle connecting rod 42 to form the fifth rotating pair.

[0025] The first rotating shaft axis connecting the fourth Hooke hinge 44 and the fourth outer connecting rod 43 is parallel to the axes of the fourth and fifth rotating joints and perpendicular to the axis of the fourth translating joint. In the two first branches, the axes of the two first prismatic joints coincide, and the axes of the two first and second revolute joints are parallel; The second rotation axis of the fourth Hooke's hinge in the fourth branch is parallel to the axis of the first rotational joint in the first branch; 4. Motion characteristics The drive pairs are the prismatic joints on each branch and the fifth revolute joint on the fourth branch. The drive method can be ball screw or hydraulic drive. From the beginning, by controlling the movement of the six drive pairs, the robot can generate redundant degrees of freedom, reduce input singular configurations, increase the rotation angle of the moving platform, and improve the flexibility of the mechanism. Example

[0026] like Figure 3 , 6 As shown in Figures 7 and 9, this embodiment adopts a configuration of two PRRR side branches + one PRPU middle branch: 1. Branching structure (a) Lateral branch (second branch / PRRR type): Second moving pair: The sliding block (21) of the moving pair cooperates with the upper guide rail of the frame (2). The seventh revolute joint: the slider (21) and the connecting rod (22) are fitted through the hole (vertical axis). Eighth rotating joint: through-hole fit between the middle connecting rod (22) and the outer connecting rod (23) (horizontal axis) Sixth revolute joint: The end of the outer connecting rod (23) is connected to the moving platform (5) (the axis is parallel to the seventh revolute joint). (b) Intermediate Branch (same as PRPU type in Example 1): The structural configuration is the same as the third branch in Example 1. 2. Drive system 6 drive pairs: ①: The second moving joint of the left PRRR branch ②: The seventh revolute joint (rotational drive) of the left PRRR branch ③: The second moving joint of the right-side PRRR branch ④: The seventh revolute joint (rotation drive) of the right PRRR branch ⑤-⑥: The third and fourth moving sub-parts of the PRPU branch 3. Geometric Constraints The second sliding pair slider 21 cooperates with the first sliding pair guide rail fixed on the frame to form a second sliding pair. The second sliding pair slider 21 cooperates with the through hole of the second middle connecting rod 22 to form a seventh rotating pair. The second outer connecting rod 23 cooperates with the through hole of the second middle connecting rod 22 to form an eighth rotating pair. The third sliding pair slider 31 cooperates with the third sliding pair guide rail fixed on the frame to form the third sliding pair. The third sliding pair slider 31 cooperates with the through hole of the third sliding pair outer connecting rod 32 to form the ninth rotating pair. The third sliding pair outer connecting rod 32 cooperates with the third sliding pair inner connecting rod 32 to form the third sliding pair.

[0027] The first rotating shaft axis connecting the third Hooke hinge 34 and the inner connecting rod 33 of the third sliding joint is parallel to the axis of the ninth rotating joint and perpendicular to the axis of the third sliding joint. In the two second branches, the axes of the two second prismatic joints coincide, and the axes of the two seventh and eighth revolute joints are parallel; The second rotation axis of the third Hooke hinge in the third branch is parallel to the axis of the seventh rotation joint in the second branch; 4. Accuracy Optimization The drive pairs are the prismatic joints on each branch and the seventh revolute joint on the second branch. The drive method can be either ball screw or hydraulic drive. From the beginning, by controlling the movement of the six drive pairs, the robot can generate redundant degrees of freedom, reduce input singular configurations, increase the rotation angle of the moving platform, and improve the flexibility of the mechanism. Example

[0028] like Figure 4 , 6 As shown in Figures 8 and 9, this embodiment adopts a configuration of two PRRR side branches + one PRRU middle branch: 1. Branching structure (a) Side branch (same as PRRR type in Example 3): The structural configuration is exactly the same as in Example 3. (b) Intermediate Branch (same as PRRU type in Example 2): The structural configuration is the same as the fourth branch in Example 2. 2. Drive system 6 drive pairs: ①-②: The second prismatic joint and the seventh revolute joint of the left PRRR branch ③-④: The second prismatic joint and the seventh revolute joint of the right-side PRRR branch ⑤: The fourth moving sub-branch of the PRRU branch ⑥: The fifth revolute joint of the PRRU branch 3. Geometric Constraints The second sliding pair slider 21 cooperates with the first sliding pair guide rail fixed on the frame to form a second sliding pair. The second sliding pair slider 21 cooperates with the through hole of the second middle connecting rod 22 to form a seventh rotating pair. The second outer connecting rod 23 cooperates with the through hole of the second middle connecting rod 22 to form an eighth rotating pair. The fourth sliding pair slider 41 cooperates with the third sliding pair guide rail fixed on the frame to form the fourth sliding pair. The fourth sliding pair slider 41 cooperates with the through hole of the fourth middle connecting rod 42 to form the fourth rotating pair. The fourth outer connecting rod 43 cooperates with the through hole of the fourth middle connecting rod 42 to form the fifth rotating pair.

[0029] The first rotating shaft axis connecting the fourth Hooke hinge 44 and the fourth outer connecting rod 43 is parallel to the axes of the seventh and eighth rotating joints and perpendicular to the axis of the fourth translating joint. In the two second branches, the axes of the two second prismatic joints coincide, and the axes of the two seventh and eighth revolute joints are parallel; The second rotation axis of the fourth Hooke's hinge in the fourth branch is parallel to the axes of the seventh and eighth rotational joints in the second branch; 4. Dynamic performance The drive pairs are the prismatic joints on each branch, and the fifth and ninth rotary joints on the second and fourth branches. The drive method can be ball screw or hydraulic drive. From the beginning, by controlling the movement of the six drive pairs, the robot can generate redundant degrees of freedom, reduce input singular configurations, increase the rotation angle of the moving platform, and improve the flexibility of the mechanism.

[0030] The above embodiments merely illustrate several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

[0031] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A structurally symmetrical, motion-redundant, five-degree-of-freedom hybrid machining robot, characterized in that: Includes base (10), column (1), frame (2), two symmetrically arranged side branches (3), one middle branch (4), moving platform (5), cutting tool (6), worktable (7), X-axis slide (8), Y-axis slide (9); The base (10) is fixed to the ground, the column (1) is vertically installed on the base (10), and the frame (2) is installed on the column (1); The upper ends of the two side branches (3) and one middle branch (4) are connected to the frame (2) through a sliding joint; the lower ends of the two side branches (3) are connected to the moving platform (5) through a rotating joint; the lower end of the middle branch (4) is connected to the moving platform (5) through a Hooke joint; the cutting tool (6) is mounted on the electric spindle, and the electric spindle is fixed at the center of the moving platform (5); The worktable (7) is connected to the X-axis slide (8) via a rotating joint. The X-axis slide (8) is connected to the Y-axis slide (9) via a guide rail. The Y-axis slide (9) is connected to the base (10) via a guide rail. The moving platform (5) has a degree of freedom to rotate about the Y-axis and a degree of freedom to move along the Z-axis. The worktable (7) has a degree of freedom to rotate about the X-axis. The X-axis slide (8) has a degree of freedom to move along the X-axis. The Y-axis slide (9) has a degree of freedom to move along the Y-axis. The robot achieves five-degree-of-freedom motion and motion redundancy control through six drive pairs, which are distributed on the side branch (3) and the middle branch (4).

2. The structurally symmetrical, motion-redundant, five-degree-of-freedom hybrid machining robot according to claim 1, characterized in that: The upper ends of the side branches (3) and the middle branches (4) are connected to the frame (2) at the same height and arranged horizontally; The axis of the rotating joint connecting the lower end of the side branch (3) to the moving platform (5) is parallel to each other and perpendicular to the Hooke pair X-direction axis of the middle branch (4); The rotational subcenters of the two lateral branches (3) and the Hooke subcenter of the middle branch (4) form an isosceles right triangle.

3. A structurally symmetrical, motion-redundant, five-degree-of-freedom hybrid machining robot according to claim 1 or 2, characterized in that: The side branch (3) is a PRPR branch, which includes a sliding joint (P), a revolute joint (R), a sliding joint (P), and a revolute joint (R) connected in sequence, and its structure is as follows: The sliding block (11) and the guide rail of the frame (2) form the first sliding pair; The slider (11) and the telescopic outer rod (12) through hole cooperate to form the first rotating pair; The telescopic outer rod (12) and the telescopic inner rod (13) form a second sliding pair; The end of the telescopic inner rod (13) is connected to the moving platform (5) through the second rotating joint.

4. The structurally symmetrical, motion-redundant, five-degree-of-freedom hybrid machining robot according to claim 3, characterized in that: The intermediate branch (4) is a PRPU branch, which includes a sliding joint (P), a revolute joint (R), a sliding joint (P), and a Hooke joint (U) connected in sequence. Its structure is as follows: The sliding block (31) of the moving pair forms a third moving pair with the guide rail of the frame (2); The slider (31) and the telescopic outer rod (32) through hole cooperate to form a third rotating pair; The telescopic outer rod (32) and the telescopic inner rod (33) form a fourth sliding pair; The end of the telescopic inner rod (33) is connected to the moving platform (5) through the Hooke hinge (34), and the first rotating shaft of the Hooke hinge is parallel to the axis of the third rotating pair.

5. A structurally symmetrical, motion-redundant, five-degree-of-freedom hybrid machining robot according to claim 3, characterized in that: The intermediate branch (4) is a PRRU branch, which includes a sliding joint (P), a revolute joint (R), a revolute joint (R), and a Hooke's joint (U) connected in sequence. Its structure is as follows: The sliding block (41) of the moving pair forms a fourth moving pair with the guide rail of the frame (2); The slider (41) and the connecting rod (42) through hole form a fourth rotating pair; The middle connecting rod (42) and the outer connecting rod (43) are fitted together through the hole to form the fifth rotating pair; The end of the outer connecting rod (43) is connected to the moving platform (5) through the Hooke hinge (44), and the first axis of the Hooke hinge is parallel to the axis of the fifth rotating pair.

6. A structurally symmetrical, motion-redundant, five-degree-of-freedom hybrid machining robot according to claim 1 or 2, characterized in that: The side branch (3) is a PRRR branch, which includes a sliding joint (P), a revolute joint (R), a revolute joint (R), and a revolute joint (R) connected in sequence, and its structure is as follows: The sliding block (21) of the movable pair forms a second movable pair with the guide rail of the frame (2); The slider (21) and the connecting rod (22) through hole form the seventh rotating pair; The middle connecting rod (22) and the outer connecting rod (23) are fitted together through the hole to form the eighth rotating pair; The end of the outer connecting rod (23) is connected to the moving platform (5) through the sixth rotating joint.

7. A structurally symmetrical, motion-redundant, five-degree-of-freedom hybrid machining robot according to claim 6, characterized in that: The intermediate branch (4) is a PRPU branch, which includes a sliding joint (P), a revolute joint (R), a sliding joint (P), and a Hooke joint (U) connected in sequence. Its structure is as follows: The sliding block (31) of the moving pair forms a third moving pair with the guide rail of the frame (2); The slider (31) and the outer connecting rod (32) through hole cooperate to form the ninth rotating pair; The outer link (32) and the inner link (33) form the fifth sliding joint; The end of the inner connecting rod (33) is connected to the moving platform (5) through the Hooke hinge (34), and the first axis of the Hooke hinge is parallel to the axis of the ninth rotating pair.

8. A structurally symmetrical, motion-redundant, five-degree-of-freedom hybrid machining robot according to claim 6, characterized in that: The intermediate branch (4) is a PRRU branch, which includes a sliding joint (P), a revolute joint (R), a revolute joint (R), and a Hooke's joint (U) connected in sequence. Its structure is as follows: The sliding block (41) of the moving pair forms a fourth moving pair with the guide rail of the frame (2); The slider (41) and the connecting rod (42) through hole form a fourth rotating pair; The middle connecting rod (42) and the outer connecting rod (43) are fitted together through the hole to form the fifth rotating pair; The end of the outer connecting rod (43) is connected to the moving platform (5) through the Hooke hinge (44), and the first axis of the Hooke hinge is parallel to the axis of the fifth rotating pair.

9. A structurally symmetrical, motion-redundant, five-degree-of-freedom hybrid machining robot according to claim 1, characterized in that: The worktable (7), X-axis slide (8), and Y-axis slide (9) constitute a series motion chain, the structure of which is as follows: The worktable (7) is connected to the X-axis slide (8) via a rotary joint (51) to achieve rotation around the X-axis; The X-axis slide (8) is connected to the Y-axis slide (9) via the guide rail pair (52) to achieve X-axis movement; The Y-axis slide (9) is connected to the base (10) through the guide rail pair (53) to achieve Y-axis movement.

10. A structurally symmetrical, motion-redundant, five-degree-of-freedom hybrid machining robot according to claim 1, characterized in that: The six drive pairs are selected from one of the following combinations: (a) Four moving parts of two PRPR branches + two moving parts of the PRPU branch; (b) Four moving joints of two PRPR branches + one moving joint and one revolute joint (fifth revolute joint) of the PRRU branch. (c) Two prismatic joints and two revolute joints (seventh revolute joint) of the two PRRR branches + two prismatic joints of the PRPU branch; (d) Two translating joints and two revolute joints (seventh revolute joint) of two PRRR branches + one translating joint and one revolute joint (fifth revolute joint) of the PRRU branch.

Images