A three-translation and one-rotation four-degree-of-freedom redundant drive parallel mechanism

Abstract

The present invention belongs to the technical field of industrial robots and discloses a three-movement, one-rotation, four-degree-of-freedom redundant drive parallel mechanism, comprising a fixed platform and a movable platform; a plurality of motion branches are provided between the fixed platform and the movable platform; the motion branches comprise a first arc-shaped connecting rod and a second arc-shaped connecting rod that are bent in opposite directions, and the first arc-shaped connecting rod and the second arc-shaped connecting rod are slidably connected to each other; one end of the first arc-shaped connecting rod cooperates with the fixed platform, and the first arc-shaped connecting rod can rotate around an axis perpendicular to the fixed platform; one end of the second arc-shaped connecting rod is movably connected to the movable platform; the first arc-shaped connecting rod is equipped with a first drive motor for driving the first arc-shaped connecting rod to rotate around an axis parallel to the fixed platform; the second arc-shaped connecting rod is equipped with an auxiliary motor for driving the second arc-shaped connecting rod to slide relative to the first arc-shaped connecting rod. The present invention can improve the operational smoothness and accuracy of the parallel mechanism, improve the load-bearing capacity of the motion pair, and improve the overall performance of the mechanism.

Description

Technical Field

[0001] The present invention belongs to the technical field of industrial robots, and in particular relates to a three-translation-one-rotation four-degree-of-freedom redundant drive parallel mechanism. Background Art

[0002] Parallel mechanisms are spatial multi-degree-of-freedom mechanisms. Their main feature is that they connect a fixed platform and a moving platform via two or more branch chains, forming a multi-closed-loop structure. Compared to serial mechanisms, parallel mechanisms have advantages such as greater structural rigidity and load-bearing capacity, higher positioning accuracy, and easier control. A redundantly driven parallel mechanism is one in which the number of its drive devices exceeds the number of degrees of freedom. It has advantages such as local symmetry, effective elimination of singular configurations within the workspace, and improved force characteristics of the mechanism. Therefore, it is often used in simulators, machine tools, positioning platforms, and other fields with large loads or high dynamic performance requirements.

[0003] Among existing low-DOF redundantly driven parallel mechanisms, the invention patent with publication number CN115592653B proposes a planar three-DOF redundantly driven parallel mechanism. Its four parallel branches are evenly spaced along the outer periphery of the moving platform, forming a regular quadrilateral arrangement connecting the moving platform. The parallel branches rotate the rotating rods and drive the telescopic rods to perform telescopic drive, forming a redundantly driven over-constrained parallel mechanism, allowing the moving platform to perform planar x- and y-axis movement and rotation around the z-axis. The patent application with publication number CN110181487A proposes a highly dexterous two-rotation-one-shift redundantly driven parallel mechanism. It uses four identical RPRU branches, which greatly improves the stability, stiffness, and fault tolerance of the mechanism. The invention patent with publication number CN114654454B proposes a three-branch motion redundant parallel mechanism driven by a moving sub-drive. It uses three hybrid branches with three identical structures, giving the parallel mechanism the characteristic of a large rotation angle.

[0004] Existing redundantly driven parallel mechanisms with three translations and one rotation, four degrees of freedom, suffer from low stiffness, poor precision, flexibility, and load-bearing capacity, and are difficult to control. Furthermore, the kinematic pairs of these mechanisms utilize both revolute and translatory pairs, with the axes of these pairs being parallel or coplanar. The connection between two adjacent connecting rods often utilizes a single kinematic pair (revolute / translatory pair). This results in excessive load-bearing capacity for these kinematic pairs, limited workspace and flexibility, and difficulty in avoiding singularities, further impacting the overall performance of the mechanism. Summary of the Invention

[0005] The purpose of the present invention is to provide a three-translation and one-rotation four-degree-of-freedom redundant drive parallel mechanism, which can improve the operation smoothness and accuracy of the parallel mechanism, improve the load-bearing capacity of the kinematic pair, and improve the overall performance of the mechanism.

[0006] To achieve the above objectives, the present invention adopts the following technical solutions:

[0007] A three-movement, one-rotation, four-degree-of-freedom redundant drive parallel mechanism, comprising a fixed platform and a moving platform; the fixed platform and the moving platform are arranged in parallel;

[0008] At least two motion branches are provided between the fixed platform and the moving platform;

[0009] The kinematic branch chain includes a first arc-shaped link and a second arc-shaped link that are curved in opposite directions, one end of the first arc-shaped link and one end of the second arc-shaped link being slidably connected to each other; an end of the first arc-shaped link away from the second arc-shaped link is engaged with a fixed platform, and the first arc-shaped link is capable of rotating around an axis perpendicular to the fixed platform; an end of the second arc-shaped link away from the first arc-shaped link is connected to a movable platform, and the second arc-shaped link and the movable platform are movably connected;

[0010] A first driving motor is configured at one end of the first arc-shaped connecting rod away from the second arc-shaped connecting rod, which is used to drive the first arc-shaped connecting rod to rotate around an axis parallel to the fixed platform; an auxiliary motor is configured at one end of the second arc-shaped connecting rod away from the movable platform, which is used to drive the second arc-shaped connecting rod to slide relative to the first arc-shaped connecting rod.

[0011] With the above technical solution, the auxiliary motor drives the second arc-shaped link to interact with the first arc-shaped link. At the same time, the first arc-shaped link can slide relative to the second arc-shaped link, thereby enabling the kinematic branch to extend or contract in its length direction. Similarly, the first drive motor drives the corresponding first arc-shaped link to rotate around the output axis of the first drive motor, which also causes the first arc-shaped link to slide relative to the second arc-shaped link, thereby driving the second arc-shaped link to slide relative to the first arc-shaped link, thereby causing the kinematic branch to extend or contract in its length direction. In addition, the first arc-shaped link can rotate around an axis perpendicular to the fixed platform. In this way, the moving platform can achieve four degrees of freedom: movement along the X, Y, and Z axes, and rotation around the Z axis, and the axis is not fixed when it rotates around the Z axis.

[0012] The first and second curved links are coupled to each other, creating two kinematic pairs between them. This further increases the load-bearing capacity of these pairs. The auxiliary motor provides redundant drive, also helping to improve the load-bearing capacity of multiple movable joints in the parallel mechanism. The flexible connection between the second curved link and the moving platform, combined with their curved structure and the two kinematic pairs between them, further expands the parallel mechanism's workspace and improves its flexibility, while also avoiding singularities.

[0013] When a singularity point occurs, the first curved link rotates around an axis perpendicular to the fixed platform, eliminating the singularity's effects and improving the parallel mechanism's operational smoothness while expanding its workspace. Driven by the first drive motor and the auxiliary motor, the first and second curved links slide relative to each other, guiding and constraining each other's motion through their curved shapes, thereby enhancing the parallel mechanism's operational precision.

[0014] According to one embodiment of the present invention, the first arc-shaped connecting rod is provided with a first arc-shaped groove, which extends along the arc length direction of the first arc-shaped connecting rod; the second arc-shaped connecting rod is provided with a second arc-shaped groove, which extends along the arc length direction of the second arc-shaped connecting rod; the end of the first arc-shaped connecting rod away from the fixed platform is in sliding engagement with the second arc-shaped groove; the end of the second arc-shaped connecting rod away from the movable platform is in sliding engagement with the first arc-shaped groove.

[0015] Furthermore, a first pin is configured at the end of the first and second curved connecting rods where they slide together, and the first pin slides in engagement with the second curved groove. A second pin is configured at the end of the second curved connecting rods where they slide together, and the second pin slides in engagement with the first curved groove. Furthermore, the second pin serves as the output shaft of the auxiliary motor.

[0016] Therefore, the first arc groove and the second arc groove are used to strengthen the guidance, restriction and constraint of the running trajectory of the second arc link and the first arc link, which can further improve the running smoothness of the parallel mechanism; and the first arc groove and the second arc groove extend along the arc length direction of the first arc link and the second arc link respectively, which can ensure that the working space of the parallel mechanism is maximized.

[0017] Furthermore, the radius and arc shape of the first arc-shaped connecting rod are equal to those of the second arc-shaped connecting rod.

[0018] Furthermore, the radii and arc lengths of the first arc-shaped connecting rod and the second arc-shaped connecting rod are not equal.

[0019] In this way, the radius and arc length of the first arc-shaped connecting rod and the second arc-shaped connecting rod can be set to be equal or unequal according to the requirements of the working space, thereby achieving the adjustment of the activity space of the parallel mechanism.

[0020] According to one embodiment of the present invention, the output shaft of the auxiliary motor is sleeved inside the first arc-shaped groove, and the end of the output shaft of the auxiliary motor is provided with a gear, and the first arc-shaped connecting rod is provided with a rack extending along the arc length, and the gear is meshed with the rack.

[0021] Driven by the auxiliary motor, the curved rack and gear mate. The gear rotates under the auxiliary motor's drive, driving the end of the second curved connecting rod to slide within the first curved slot, causing the kinematic branch to extend or contract along its length. This coordinated structure of the gear and rack enhances the smoothness and stability of this operation, preventing stalls and eliminating singularities.

[0022] According to one embodiment of the present invention, a support frame is provided in the direction of the first arc-shaped connecting rod away from the second arc-shaped connecting rod, and one end of the first arc-shaped connecting rod away from the second arc-shaped connecting rod cooperates with the support frame, and the support frame can rotate around an axis perpendicular to the fixed platform.

[0023] Furthermore, the output shaft of the first drive motor is sleeved on the support frame and is arranged parallel to the fixed platform; the end of the first arc-shaped connecting rod away from the second arc-shaped connecting rod is sleeved on the output shaft of the first drive motor, so that the output shaft of the first drive motor can drive the first arc-shaped connecting rod to rotate around an axis parallel to the fixed platform.

[0024] In this way, the support frame is used to connect the first drive motor and the first arc-shaped connecting rod, and the support frame is coordinated with the fixed platform for rotation. The support frame can drive the first arc-shaped connecting rod to rotate around an axis perpendicular to the fixed platform. This can further avoid singular points and improve the flexibility of the parallel mechanism.

[0025] According to one embodiment of the present invention, the support frame includes two symmetrically arranged support arms, and the two support arms extend toward the moving platform; the output shaft of the first drive motor is inserted in parallel inside the two support arms, and the end of the first arc-shaped connecting rod away from the second arc-shaped connecting rod is arranged between the two support arms and is sleeved on the output shaft of the first drive motor.

[0026] According to one embodiment of the present invention, the fixed platform is equipped with a second drive motor, and at least one support frame cooperates with the output end of the second drive motor. The second drive motor is used to drive the support frame connected thereto and the first arc-shaped connecting rod to rotate around an axis perpendicular to the fixed platform.

[0027] According to one embodiment of the present invention, a support rod is provided between the second arc-shaped connecting rod and the movable platform, and both ends of the support rod are rotatably engaged with the second arc-shaped connecting rod and the movable platform respectively.

[0028] In this way, the singularity point can be further avoided by the support rod, the smoothness of the operation of the parallel mechanism can be improved, and the working space and flexibility of the parallel mechanism can be further expanded.

[0029] Furthermore, a rotating shaft is inserted through both ends of the support rod, and the two rotating shafts are respectively connected to the second arc-shaped connecting rod and the movable platform; the support rod can rotate relative to the axis of the rotating shaft.

[0030] Furthermore, the movable platform is equipped with a first connecting member, which includes two symmetrically arranged connecting arms extending toward the fixed platform; the rotation axis away from the second arc-shaped connecting rod is inserted into the two connecting arms of the first connecting member.

[0031] Thus, the coordination of the support rod and the rotating shaft improves the flexibility of movement between the second curved link and the movable platform, further expanding the movable range of the movable platform. The coordination of the support rod and the rotating shaft further eliminates singular points during the operation of the first and second curved links, thereby improving the smoothness of the movable platform's operation.

[0032] Compared with the prior art, the present invention has at least the following beneficial effects:

[0033] 1. The first arc-shaped connecting rod and the second arc-shaped connecting rod are coupled to each other, and there are two kinematic pairs between them, which can further improve the load-bearing capacity of the kinematic pairs. The setting of the auxiliary motor forms a redundant drive, which also helps to improve the load-bearing capacity of multiple movable joints in the parallel mechanism.

[0034] 2. The movable connection between the second curved link and the moving platform, combined with the curved structures of the first and second curved links, and the two kinematic pairs between them, further expands the parallel mechanism's workspace and improves its flexibility, while also avoiding singularities. The first and second curved links slide relative to each other, guiding and constraining each other's motion trajectory through their own curved shapes, helping to improve the parallel mechanism's operational precision.

[0035] 3. The first arc-shaped connecting rod is equipped with a rack extending along the arc length and meshing with the gear at the end of the second arc-shaped connecting rod, which can improve the stability and smoothness of the operation process of the first arc-shaped connecting rod and the second arc-shaped connecting rod, avoid operation jams and eliminate singular points. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] The accompanying drawings, which constitute part of the present invention, are intended to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are intended to explain the present invention and do not constitute an undue limitation of the present invention. In the accompanying drawings:

[0037] Figure 1 Schematic diagram of the overall structure of a three-translation-one-rotation four-degree-of-freedom redundant drive parallel mechanism according to Example 1 of the present invention;

[0038] Figure 2 This is a schematic structural diagram of the kinematic branch of the three-translation-one-rotation four-degree-of-freedom redundant drive parallel mechanism according to Example 1 of the present invention;

[0039] Figure 3This is a schematic structural diagram of the first arc-shaped connecting rod of the three-translation-one-rotation four-degree-of-freedom redundant drive parallel mechanism according to Example 1 of the present invention;

[0040] Figure 4 This is a schematic structural diagram of the second arc-shaped connecting rod of the three-translation-one-rotation four-degree-of-freedom redundant drive parallel mechanism according to Example 1 of the present invention;

[0041] Figure 5 This is a schematic structural diagram of the extended state of the motion branch of the three-translation-one-rotation four-degree-of-freedom redundant drive parallel mechanism according to Example 1 of the present invention;

[0042] Figure 6 This is a structural schematic diagram of the contracted state of the motion branches of the three-translation-one-rotation four-degree-of-freedom redundant drive parallel mechanism of Example 1 of the present invention.

[0043] Figure numerals: fixed platform 10; movable platform 20; moving branch chain 30; first arc-shaped connecting rod 41; second arc-shaped connecting rod 42; support rod 43; first arc-shaped groove 44; second arc-shaped groove 45; first pin 46; rack 47; gear 48; support frame 50; support arm 51; rotating shaft 52; first connecting member 53; connecting arm 54; second connecting member 55; first drive motor 61; second drive motor 62; auxiliary motor 63. DETAILED DESCRIPTION

[0044] The present invention will be described in detail below with reference to the accompanying drawings and in combination with embodiments. It should be noted that, in the absence of conflict, the embodiments and features of the embodiments of the present invention can be combined with each other.

[0045] The following detailed description is an exemplary description and is intended to provide further detailed description of the present invention. Unless otherwise indicated, all technical terms used in the present invention have the same meaning as those generally understood by those skilled in the art to which the present invention belongs. The terms used in the present invention are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present invention.

[0046] Example 1

[0047] A three-translation and one-rotation four-degree-of-freedom redundant drive parallel mechanism, such as Figures 1-6 As shown, it includes a fixed platform 10 and a moving platform 20 arranged in parallel; at least two motion branches 30 are provided between the fixed platform 10 and the moving platform 20; in this embodiment, three motion branches 30 are arranged in a circular array between the fixed platform 10 and the moving platform 20.

[0048] The moving branch chain 30 includes a first arc-shaped link 41, a second arc-shaped link 42 and a support rod 43 connected in sequence; the first arc-shaped link 41 and the second arc-shaped link 42 are movably matched, and the two are bent in opposite directions; the end of the first arc-shaped link 41 away from the second arc-shaped link 42 is connected to the fixed platform 10, and at least one first arc-shaped link 41 can rotate around an axis perpendicular to the fixed platform 10, the end of the second arc-shaped link 42 away from the first arc-shaped link 41 is rotatably matched with the support rod 43, and the end of the support rod 43 away from the second arc-shaped link 42 is rotatably matched with the movable platform 20 through the support rod 43.

[0049] A first driving motor 61 is configured at one end of the first arc-shaped link 41 away from the second arc-shaped link 42, for driving the first arc-shaped link 41 to rotate around an axis parallel to the fixed platform 10; an auxiliary motor 63 is configured at one end of the second arc-shaped link 42 away from the support rod 43, for driving the second arc-shaped link 42 to slide relative to the first arc-shaped link 41.

[0050] The auxiliary motor 63 drives the second curved link 42 to interact with the first curved link 41. At the same time, the first curved link 41 can slide relative to the second curved link 42, thereby enabling the kinematic branch 30 to extend or contract along its length. Similarly, the first drive motor 61 drives the corresponding first curved link 41 to rotate about the output axis of the first drive motor 61, which also causes the first curved link 41 to slide relative to the second curved link 42, thereby driving the second curved link 42 to slide relative to the first curved link 41, thereby causing the kinematic branch 30 to extend or contract along its length. In addition, the first curved link 41 can rotate about an axis perpendicular to the fixed platform 10, thereby enabling the movable platform 20 to move along the X, Y, and Z axes and rotate about the Z axis in four degrees of freedom, and the axis is not fixed when it rotates about the Z axis.

[0051] The first and second curved links 41 and 42 are coupled to each other, creating two kinematic pairs between them. This further increases the load-bearing capacity of these pairs. The provision of auxiliary motor 63 creates a redundant drive, also helping to improve the load-bearing capacity of multiple movable joints in the parallel mechanism. The flexible connection between the second curved link 42 and the movable platform 20, combined with the curved structure of the first and second curved links 41 and 42, and the two kinematic pairs between them, further expands the parallel mechanism's workspace and improves its flexibility, while also avoiding singularities.

[0052] When a singularity point occurs, the first curved link 41 can rotate about an axis perpendicular to the fixed platform 10, eliminating the effects of the singularity, expanding the workspace while improving the smoothness of the parallel mechanism's operation. Driven by the first drive motor 61 and the auxiliary motor 63, the first curved link 41 and the second curved link 42 slide relative to each other. During this process, their curved shapes guide and constrain each other's motion trajectory, helping to improve the precision of the parallel mechanism's operation.

[0053] Furthermore, the first arc-shaped connecting rod 41 is provided with a first arc-shaped groove 44, which extends along the arc length direction of the first arc-shaped connecting rod 41; the second arc-shaped connecting rod 42 is provided with a second arc-shaped groove 45, which extends along the arc length direction of the second arc-shaped connecting rod 42; the end of the first arc-shaped connecting rod 41 away from the fixed platform 10 is slidably engaged with the second arc-shaped groove 45; the end of the second arc-shaped connecting rod 42 away from the support rod 43 is slidably engaged with the first arc-shaped groove 44.

[0054] The first arc-shaped groove 44 and the second arc-shaped groove 45 are both through grooves, thereby reducing the mass of the motion branch chain 30 .

[0055] In this embodiment, the radius and arc length of the first arc-shaped connecting rod 41 and the second arc-shaped connecting rod 42 are equal. In other embodiments, the radius and arc length of the first arc-shaped connecting rod 41 and the second arc-shaped connecting rod 42 can be set to be equal or different according to the requirements of the working space, thereby adjusting the movable space of the parallel mechanism.

[0056] Furthermore, a first pin 46 is provided at the end where the first and second curved connecting rods 41 and 42 slide together. The first pin 46 slides in engagement with the second curved slot 45. The end where the second curved connecting rod 42 slides in engagement with the first curved connecting rod 41 is sleeved onto the output shaft of the auxiliary motor 63. The output shaft of the auxiliary motor 63 slides in engagement with the first curved slot 44. The auxiliary motor 63 can drive the second curved connecting rod 42 to rotate about the axis of the output shaft of the auxiliary motor 63, thereby driving the second curved connecting rod 42 to slide within the first curved slot 44.

[0057] The output shaft of the auxiliary motor 63 is terminated with a gear 48. The first curved connecting rod 41 is equipped with a rack 47 extending along the length of the arc, with the gear 48 meshing with the rack 47. Driven by the auxiliary motor 63, the curved rack 47 engages with the gear 48. Driven by the auxiliary motor 63, the gear 48 rotates, driving the end of the second curved connecting rod 42 to slide within the first curved slot 44, causing the kinematic branch 30 to extend or contract along its length. The coordinated structure of the gear 48 and rack 47 enhances the smoothness and stability of the operation, preventing operational stalls and eliminating singularities.

[0058] A support frame 50 is provided in the direction of the first arc-shaped connecting rod 41 away from the second arc-shaped connecting rod 42 . One end of the first arc-shaped connecting rod 41 away from the second arc-shaped connecting rod 42 cooperates with the support frame 50 . The support frame 50 can rotate around an axis perpendicular to the fixed platform 10 .

[0059] Furthermore, the output shaft of the first drive motor 61 is sleeved on the support frame 50 and is arranged parallel to the fixed platform 10; the end of the first arc-shaped connecting rod 41 away from the second arc-shaped connecting rod 42 is sleeved on the output shaft of the first drive motor 61, so that the output shaft of the first drive motor 61 can drive the first arc-shaped connecting rod 41 to rotate around an axis parallel to the fixed platform 10.

[0060] The support frame 50 includes two symmetrically arranged support arms 51, and the two support arms 51 extend toward the moving platform 20; the output shaft of the first drive motor 61 is inserted parallel to the inside of the two support arms 51, and the end of the first arc-shaped connecting rod 41 away from the second arc-shaped connecting rod 42 is arranged between the two support arms 51, and is sleeved on the output shaft of the first drive motor 61.

[0061] The fixed platform 10 is equipped with a second drive motor 62 , and at least one support frame 50 cooperates with the output end of the second drive motor 62 . The second drive motor 62 is used to drive the support frame 50 and the first arc-shaped connecting rod 41 connected thereto to rotate around an axis perpendicular to the fixed platform 10 .

[0062] The support frame 50 is used to connect the first drive motor 61 and the first arc-shaped connecting rod 41, and the support frame 50 is coordinated with the fixed platform 10 for rotation. The support frame 50 can drive the first arc-shaped connecting rod 41 to rotate around an axis perpendicular to the fixed platform 10. In particular, under the drive of the second drive motor 62, the motion branch chain 30 connected thereto rotates around an axis perpendicular to the fixed platform 10, and drives the other two motion branches 30 to rotate around an axis perpendicular to the fixed platform 10, which can further avoid singular points and improve the flexibility of the parallel mechanism.

[0063] A support rod 43 is provided between the second arc-shaped connecting rod 42 and the movable platform 20 . Both ends of the support rod 43 are rotatably engaged with the second arc-shaped connecting rod 42 and the movable platform 20 , respectively.

[0064] In this way, the support rod 43 can be used to further avoid singular points, thereby improving the smoothness of the operation of the parallel mechanism; and further expanding the working space and flexibility of the parallel mechanism.

[0065] Furthermore, a rotation shaft 52 is inserted through both ends of the support rod 43 , and the two rotation shafts 52 are respectively connected to the second arc-shaped connecting rod 42 and the movable platform 20 ; the support rod 43 can rotate relative to the axis of the rotation shaft 52 .

[0066] Furthermore, the movable platform 20 is configured with a first connecting member 53, which includes two symmetrically arranged connecting arms 54, which extend toward the fixed platform 10; the rotating shaft 52 provided at the end of the support rod 43 away from the second arc-shaped connecting rod 42 is inserted into the two connecting arms 54 of the first connecting member 53.

[0067] Furthermore, a second connecting member 55 is provided at one end of the second arc-shaped connecting rod 42 close to the supporting rod 43. The second connecting member 55 may be configured to have the same structure as the first connecting member 53 or a different structure from the first connecting member 53. Figure 2 In this embodiment, the second connecting member 55 is a block-shaped structure, which is different from the first connecting member 53. The rotation axis 52 provided at the end of the support rod 43 away from the movable platform 20 is inserted into the interior of the second connecting member 55. This rotation axis 52 passes through the end of the support rod 43 away from the movable platform 20, and the support rod 43 can also rotate around this rotation axis 52 away from the movable platform 20.

[0068] Thus, the support rod 43 cooperates with the two rotation shafts 52 to form two movable joints between the second curved link 42 and the movable platform 20, thereby increasing the flexibility of the second curved link 42 and the movable platform 20 and further expanding the range of motion of the movable platform 20. The cooperation between the support rod 43 and the rotation shafts 52 and other components further eliminates singular points during the operation of the first curved link 41 and the second curved link 42, thereby improving the smooth operation of the movable platform 20.

[0069] The three-translation-one-rotation four-degree-of-freedom redundant drive parallel mechanism of this embodiment realizes translational movement in three directions and rotation in one direction, and the axis of rotation is not unique. It can be applied to virtual axis machine tools, aviation simulation equipment, medical equipment and other fields.

[0070] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the field should understand that the specific implementation methods of the present invention can still be modified or replaced by equivalents. Any modification or equivalent replacement that does not depart from the spirit and scope of the present invention should be covered by the scope of protection of the claims of the present invention.

Claims

1. A three-movement, one-rotation, four-degree-of-freedom redundant drive parallel mechanism, comprising a fixed platform (10) and a moving platform (20); characterized in that: At least two motion branches (30) are provided between the fixed platform (10) and the movable platform (20); The motion branch chain (30) includes a first arc-shaped link (41) and a second arc-shaped link (42) that are bent in the opposite direction. The first arc-shaped link (41) and the second arc-shaped link (42) are slidably connected to each other. One end of the first arc-shaped link (41) away from the second arc-shaped link (42) is matched with the fixed platform (10), and the first arc-shaped link (41) can rotate around an axis perpendicular to the fixed platform (10). One end of the first arc-shaped link (41) away from the second arc-shaped link (42) is provided with a support frame (50), and the support frame (50) can rotate around an axis perpendicular to the fixed platform (10). Rotation; one end of the second arc-shaped connecting rod (42) away from the first arc-shaped connecting rod (41) is movably connected to the movable platform (20); a support rod (43) is provided between the second arc-shaped connecting rod (42) and the movable platform (20), and both ends of the support rod (43) are respectively rotatably matched with the second arc-shaped connecting rod (42) and the movable platform (20); a rotating shaft (52) is inserted through both ends of the support rod (43), and the two rotating shafts (52) are respectively connected to the second arc-shaped connecting rod (42) and the movable platform (20); the support rod (43) can rotate relative to the axis of the rotating shaft (52); The first arc-shaped connecting rod (41) is provided with a first arc-shaped groove (44), and the first arc-shaped groove (44) extends along the arc length direction of the first arc-shaped connecting rod (41); the second arc-shaped connecting rod (42) is provided with a second arc-shaped groove (45), and the second arc-shaped groove (45) extends along the arc length direction of the second arc-shaped connecting rod (42); One end of the first arc-shaped connecting rod (41) away from the fixed platform (10) is in sliding engagement with the second arc-shaped groove (45); and one end of the second arc-shaped connecting rod (42) away from the movable platform (20) is in sliding engagement with the first arc-shaped groove (44). A first driving motor (61) is provided at one end of the first arc-shaped connecting rod (41) away from the second arc-shaped connecting rod (42) for driving the first arc-shaped connecting rod (41) to rotate around an axis parallel to the fixed platform (10); and an auxiliary motor (63) is provided at one end of the second arc-shaped connecting rod (42) away from the movable platform (20) for driving the second arc-shaped connecting rod (42) to slide relative to the first arc-shaped connecting rod (41).

2. The three-translation-one-rotation four-degree-of-freedom redundant drive parallel mechanism according to claim 1, characterized in that: The output shaft of the auxiliary motor (63) is sleeved inside the first arc-shaped slot (44), and a gear (48) is provided at the end of the output shaft of the auxiliary motor (63). The first arc-shaped connecting rod (41) is provided with a rack (47) extending along the arc length, and the gear (48) is meshed with the rack (47).

3. The three-translation-one-rotation four-degree-of-freedom redundant drive parallel mechanism according to claim 1, characterized in that: The output shaft of the first drive motor (61) is sleeved on the support frame (50) and arranged parallel to the fixed platform (10); The output shaft of the first driving motor (61) can drive the first arc-shaped connecting rod (41) to rotate around an axis parallel to the fixed platform (10).

4. The three-translation-one-rotation four-degree-of-freedom redundant drive parallel mechanism according to claim 1, characterized in that: The support frame (50) comprises two symmetrically arranged support arms (51), and the two support arms (51) are extended toward the movable platform (20); The output shaft of the first drive motor (61) is inserted into the two support arms (51) in parallel, and one end of the first arc-shaped connecting rod (41) away from the second arc-shaped connecting rod (42) is arranged between the two support arms (51) and is sleeved on the output shaft of the first drive motor (61).

5. The three-translation-one-rotation four-degree-of-freedom redundant drive parallel mechanism according to claim 1, characterized in that: The fixed platform (10) is equipped with a second drive motor (62), and at least one of the support frames (50) is matched with an output end of the second drive motor (62). The second drive motor (62) is used to drive the support frame (50) and the first arc-shaped connecting rod (41) connected thereto to rotate around an axis perpendicular to the fixed platform (10).

6. The three-translation-one-rotation four-degree-of-freedom redundant drive parallel mechanism according to claim 1, characterized in that: The movable platform (20) is provided with a first connecting member (53), the first connecting member (53) comprising two symmetrically arranged connecting arms (54), the connecting arms (54) extending toward the fixed platform (10); The rotation axis (52) away from the second arc-shaped connecting rod (42) is inserted into the two connecting arms (54) of the first connecting member (53).

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