Over-constrained six-degree-of-freedom parallel platform with self-balancing function

Abstract

The invention discloses a self-balancing over-constrained six-degree-of-freedom parallel platform, comprising: a fixed platform, the upper end face of which is circumferentially distributed with a plurality of connecting sub-plates 1; the movable platform is located above the fixed platform, and a plurality of second connecting auxiliary plates are arranged on the lower end face of the movable platform; the number of the driving rods is multiple, and each first connecting auxiliary plate and each second connecting auxiliary plate are each provided with two universal hinge shafts. The fine adjustment driven devices are arranged at the output ends of the driving rods, and the upper ends of the driving rods are connected with the universal hinge shafts on the first connecting auxiliary plate through the fine adjustment driven devices; the posture detection unit is mounted on the lower end surface of the movable platform; each driving rod is provided with two fine adjustment controllers, the fine adjustment controllers can conduct small-range and high-precision fine adjustment, and high-precision self-balancing positioning of the movable platform is achieved; and elastic floating support is realized below the movable platform, so that internal mechanical stress is effectively eliminated, and a hinge or a driving rod is prevented from being damaged due to instantaneous overload.

Description

Technical Field

[0001] This invention belongs to the field of motion platform technology, specifically a self-balancing over-constrained six-degree-of-freedom parallel platform. Background Technology

[0002] Six-DOF parallel platforms, a crucial technology in precision motion control and heavy-duty support, typically consist of a static platform, a moving platform, and six independently extendable drive rods. Through the coordinated extension and retraction of these six rods, the moving platform achieves three translational and three rotational degrees of freedom in space. These platforms, with their advantages of high rigidity, high load-bearing capacity, high precision, and zero cumulative error, are widely used in high-end equipment fields such as flight simulators, heavy equipment positioning, and precision machine tools. However, traditional platforms employ single-stage drives, which cannot simultaneously meet the needs of macro-motion and micro-motion in scenarios requiring large-scale coarse positioning and local fine-tuning.

[0003] In addition, traditional six-degree-of-freedom parallel platforms lack dedicated buffer and energy absorption structures. When redundant drives or over-constraint designs are used to improve stiffness, even small assembly errors can cause huge additional stresses inside the mechanism, and rigid hinges and drive rods are easily damaged by instantaneous overload.

[0004] Therefore, it is necessary to provide a self-balancing over-constrained six-degree-of-freedom parallel platform to solve the problems mentioned in the background art. Summary of the Invention

[0005] To achieve the above objectives, the present invention provides the following technical solution: a self-balancing, over-constrained six-degree-of-freedom parallel platform, comprising:

[0006] A fixed platform, with multiple connecting plates distributed circumferentially on its upper surface;

[0007] A moving platform is located above a fixed platform, and multiple connecting sub-plates are provided on the lower end face of the moving platform;

[0008] Multiple drive rods are provided, and each of the connecting sub-plates 1 and 2 is provided with two universal hinges. The lower end of each drive rod is connected to the universal hinge on the connecting sub-plate 1.

[0009] A fine-tuning slave is provided on the output end of each drive rod, and the upper end of the drive rod is connected to the universal hinge shaft on the connecting sub-plate through the fine-tuning slave;

[0010] An attitude detection unit is installed on the lower end face of the moving platform.

[0011] Furthermore, as a preferred embodiment, the two drive rods on the connecting sub-plate are arranged in a V-shape.

[0012] Furthermore, preferably, the attitude detection unit includes:

[0013] The slide rails are set in three and arranged in a circle on the lower end face of the moving platform;

[0014] Distance sensors are provided one-to-one with the slide rail frame. Transfer blocks are slidably mounted on the slide rail frame, and the distance sensors are all installed below the transfer blocks.

[0015] A rotating disk is rotatably mounted on a moving platform. The rotating disk has multiple inclined slots. A guide pin is vertically fixed on the transfer block, and one end of the guide pin is slidably connected in the inclined slot.

[0016] Furthermore, preferably, each of the ranging sensors is always vertically oriented towards the fixed platform;

[0017] The lower end face of the moving platform is equipped with a control motor for driving the rotating disk to rotate.

[0018] Furthermore, preferably, the fine-tuning slave includes:

[0019] A sliding shaft plate, the upper end face of which is fixed to the universal hinge shaft, and two sliders are symmetrically slidably arranged inside the sliding shaft plate;

[0020] Two fine-tuning controllers are provided, and each fine-tuning controller has a rotating hinge shaft connected to its upper and lower ends. The rotating hinge shaft located at the lower end of the fine-tuning controller is connected to the shaft in the drive rod, and the rotating hinge shaft located at the upper end of the fine-tuning controller is connected to the slider in the slide plate.

[0021] Furthermore, as a preferred embodiment, a guide shaft is fixed in the middle of the sliding plate, and a linkage rod is rotatably connected to the guide shaft. Guide grooves are symmetrically opened at both ends of the linkage rod, and a guide pin is fixed on each of the sliders. The guide pin is slidably connected to the guide groove.

[0022] Two inner springs are symmetrically connected inside the slide plate, and the other end of the inner spring is connected to the slider.

[0023] Furthermore, as a preferred embodiment, a fixed tube is coaxially slidably sleeved on the outside of the shaft, and a limit ring is fixed at the upper end of the inside of the fixed tube. The limit ring has an inner hole corresponding to the fine adjustment controller, and the limit ring is slidably sleeved on the outside of the fine adjustment controller through the inner hole.

[0024] The lower end of the shaft is coaxially sealed with a pressure ring, and the lower end of the fixed tube is slidably connected to the pressure ring. An L-shaped channel is opened inside the shaft, one end of which is connected to the pressure ring and the other end is connected to a flexible air guide. A guide seat is fixed inside the lower part of the drive rod, and the flexible air guide is connected to the guide seat.

[0025] Furthermore, as a preferred embodiment, when the limiting ring slides downward with the fixing tube and slides away from the fine-tuning controller, the two sliders slide in opposite directions under the pull of the inner spring, so that the two fine-tuning controllers are mounted in a V-shape.

[0026] Furthermore, preferably, the fine-tuning controller includes:

[0027] The guide cylinder has a shaft tube that is slidably connected to it coaxially inside.

[0028] A central rod is coaxially arranged inside the shaft tube, and the upper end of the central rod is fixed to the rotating hinge shaft;

[0029] The hydraulic chamber is centrally located within the guide cylinder, and the lower end of the central rod is slidably connected to the hydraulic chamber via a piston seal.

[0030] A hydraulic channel is provided inside the guide cylinder, and one end of the channel is sealed and connected to the hydraulic chamber.

[0031] Furthermore, as a preferred embodiment, the outer sleeve of the shaft tube is provided with an outer support spring, the inner wall of the guide cylinder is provided with a flange, the lower end of the outer support spring is connected to the flange, and its upper end is connected to the end of the central rod;

[0032] The guide cylinder has multiple sliding cavities on its inner circumference, and each of the sliding cavities is slidably connected to a support rod. The upper end of each support rod is connected to a compression spring, and the upper end of the compression spring is connected to the shaft tube.

[0033] Compared with the prior art, the beneficial effects of the present invention are:

[0034] In this invention, the moving platform of the six-degree-of-freedom parallel platform is equipped with an attitude detection unit. The attitude detection unit can detect the spatial height of the moving platform through multiple ranging sensors, thereby obtaining the attitude information of the moving platform. Two fine-tuning controllers are set on each drive rod. On the one hand, each fine-tuning controller can perform small-range, high-precision fine-tuning after the drive rod completes a large-stroke extension and retraction adjustment, realizing high-precision self-balancing positioning of the moving platform. In addition, multiple fine-tuning telescoping devices form an over-constraint effect, which can effectively improve the overall stiffness and load capacity of the platform, resulting in less deformation under heavy load or eccentric load conditions. On the other hand, when the limit ring locks the two fine-tuning controllers, the external support springs and compression springs in each fine-tuning controller can form multi-stage anti-compression and shock absorption, and can achieve elastic floating support under the moving platform, effectively eliminating internal mechanical stress, preventing damage to hinges or drive rods due to instantaneous overload, and extending service life. Attached Figure Description

[0035] Figure 1 This is a schematic diagram of the overall structure of the present invention;

[0036] Figure 2 This is a schematic diagram of the attitude detection unit in this invention;

[0037] Figure 3 This is a schematic diagram of the drive rod structure in this invention;

[0038] Figure 4 This is a schematic diagram of the internal structure of the drive rod in this invention;

[0039] Figure 5 This is a schematic diagram of the linkage mechanism in this invention;

[0040] Figure 6 This is a schematic diagram illustrating the structure of the limiting ring locking the two fine-tuning controllers in this invention.

[0041] Figure 7 This is a schematic diagram illustrating the unlocking of the limit ring from the two fine-tuning controller structures in this invention;

[0042] Figure 8 This is a schematic diagram of the fine-tuning controller in this invention;

[0043] In the diagram: 1. Fixed platform; 11. Connecting sub-plate 1; 12. Moving platform; 13. Universal hinge; 2. Attitude detection unit; 21. Slide rail frame; 22. Distance sensor; 23. Rotating disk; 24. Inclined groove; 3. Drive rod; 31. Shaft; 32. Fixed tube; 33. Air pressure ring; 34. L-shaped channel; 35. Air guide hose; 36. Air guide seat; 4. Fine-tuning slave; 41. Slide plate; 42. Rotating hinge; 43. Guide shaft; 44. Linkage rod; 45. Guide groove; 5. Fine-tuning controller; 51. Guide cylinder; 52. Shaft tube; 53. Center rod; 54. Hydraulic chamber; 55. Hydraulic channel; 56. External support spring; 57. Slide cavity; 58. Support rod; 59. Compression spring. Detailed Implementation

[0044] Please see Figures 1-8 In this embodiment of the invention, an over-constrained six-degree-of-freedom parallel platform with self-balancing capability includes:

[0045] Fixed platform 1, with multiple connecting sub-plates 11 distributed circumferentially on its upper end face;

[0046] The moving platform 12 is located above the fixed platform 1. The lower end face of the moving platform 12 is provided with multiple connecting sub-plates, and the upper end face of the moving platform 12 is used to install loads (such as simulation chambers, processing heads, optical equipment, etc.).

[0047] The drive rod 3 is configured as multiple rods, and each of the connecting sub-plate 11 and connecting sub-plate 2 is provided with two universal hinge shafts 13. The lower end of each drive rod 3 is connected to the universal hinge shaft 13 on the connecting sub-plate 11.

[0048] A fine-tuning slave 4 is installed on the output end of each drive rod 3. The upper end of the drive rod 3 is connected to the universal hinge shaft 13 on the connecting sub-plate 11 through the fine-tuning slave 4.

[0049] The attitude detection unit 2 is installed on the lower end face of the moving platform 12. The universal joint shaft 13 adopts a Hooke joint (U-shaped joint) or a ball joint (S-shaped joint) to provide two or three rotational degrees of freedom to adapt to the angle changes of the drive rod 3 and the fine-tuning slave 4 in space. The fine-tuning slave 4 can perform small-range, high-precision fine-tuning after the drive rod 3 completes large-stroke coarse positioning, to compensate for the residual error of the main drive, hinge gap, etc., and realize the high-precision positioning of the moving platform 12.

[0050] In this embodiment, the two drive rods 3 on the connecting sub-plate 11 are arranged in a V-shape. This V-shaped layout allows the two drive rods 3 to form a spatial triangular support structure in the horizontal plane, which effectively improves the resistance of the moving platform 12 to lateral forces and torsion in the horizontal direction, while avoiding mechanical interference between the drive rods and expanding the working space.

[0051] In a preferred embodiment, the attitude detection unit 2 includes:

[0052] The slide rail brackets 21 are configured as three and distributed in a circular pattern on the lower end face of the moving platform 12;

[0053] Distance sensors 22 are provided one-to-one with the slide rail frame 21. Transfer blocks are slidably mounted on the slide rail frame 21, and the distance sensors 22 are all installed below the transfer blocks.

[0054] A rotating disk 23 is rotatably mounted on the moving platform 12. Multiple inclined slots 24 are formed on the rotating disk 23. A guide pin is vertically fixed on the transfer block, with one end of the guide pin slidably connected within the inclined slot 24. Specifically, in use, to achieve self-balancing adjustment of the moving platform 12, multiple distance sensors 22 synchronously perform distance measurement operations. Each drive rod 3 can adjust the attitude of the moving platform 12 based on the distance measurement data. After adjustment, the rotating disk 23, during its rotational motion, uses the sliding action between the inclined slots 24 and the guide pin to control the radial sliding adjustment of each distance sensor 22 along the rotating disk 23. Then, each distance sensor 22 performs a secondary measurement, and the drive rod 3 can extend and retract again based on the measurement data. In the third adjustment, the fine-tuning slave 4 extends and retracts for fine-tuning, improving the adjustment accuracy, thereby achieving self-balancing of the moving platform 12.

[0055] In this embodiment, each of the ranging sensors 22 is always vertically facing the fixed platform 1;

[0056] The lower end face of the moving platform 12 is equipped with a control motor (not shown in the figure) for driving the rotating disk 23 to rotate.

[0057] In this embodiment, the fine-tuning slave 4 includes:

[0058] The upper end face of the sliding shaft plate 41 is fixed to the universal hinge shaft 13, and two sliders are symmetrically slidably arranged inside the sliding shaft plate 41.

[0059] There are two fine-tuning controllers 5. Each fine-tuning controller 5 has a rotating hinge shaft 42 connected to its upper and lower ends. The rotating hinge shaft 42 located at the lower end of the fine-tuning controller 5 is connected to the shaft 31 inside the drive rod 3, and the rotating hinge shaft 42 located at the upper end of the fine-tuning controller 5 is connected to the slider inside the sliding plate 41.

[0060] In this embodiment, a guide shaft 43 is fixed in the middle of the sliding plate 41, and a linkage rod 44 is rotatably connected to the guide shaft 43. Guide grooves 45 are symmetrically formed at both ends of the linkage rod 44, and a guide pin is fixed on each slider. The guide pin is slidably connected to the guide groove 45. With this arrangement, the ends of the two fine-tuning controllers 5 can be symmetrically distributed about the guide shaft 43.

[0061] Two inner springs are symmetrically connected inside the slide plate 41, and the other end of the inner spring is connected to the slider.

[0062] In a preferred embodiment, a fixed tube 32 is coaxially slidably sleeved on the outside of the shaft 31. A limit ring is fixed at the upper end of the inside of the fixed tube 32. The limit ring has an inner hole corresponding to the fine adjustment controller 5. The limit ring is slidably sleeved on the outside of the fine adjustment controller 5 through the inner hole. The limit ring can sleeve and limit the ends of the two fine adjustment controllers 5, so that the two fine adjustment controllers 5 and the drive rod 31 can be regarded as an integral structure.

[0063] The lower end of the shaft 31 is coaxially sealed with a pneumatic ring 33. The lower end of the fixed tube 32 is slidably connected to the pneumatic ring 33. An L-shaped channel 34 is opened inside the shaft 31. One end of the L-shaped channel 34 is connected to the pneumatic ring 33, and the other end is connected to a flexible air guide 35. A guide seat 36 is fixed inside the lower part of the drive rod 31. The flexible air guide 35 is connected to the guide seat 36. That is, the guide seat 36 can adjust the air pressure of the pneumatic ring 33 through the flexible air guide 35, and the fixed tube 32 can slide axially under the push of air pressure, so that the limit ring is disengaged from or sleeved on the ends of the two fine adjustment controllers 5.

[0064] In this embodiment, when the limiting ring slides downward with the fixing tube 32 and slides away from the fine adjustment controller 5, the two sliders slide in opposite directions under the pull of the inner spring, so that the two fine adjustment controllers 5 are set up in a V-shape. The V-shape makes the two fine adjustment controllers 5 distributed at a certain angle in space, and each applies force in different directions. In addition, compared with single-rod support, the V-shaped configuration provides bidirectional resistance to lateral forces in the horizontal plane, which significantly enhances the lateral stiffness of the platform. The platform can resist disturbances from the horizontal direction and maintain the stability of the dynamic platform posture, which is especially suitable for working conditions with vibration or wind load.

[0065] When the limit ring is locked, the two fine adjustment controllers 5 are closed, and the internal springs are in a compressed pre-tightened state.

[0066] In this embodiment, the fine-tuning controller 5 includes:

[0067] Guide cylinder 51, with shaft tube 52 slidably connected coaxially inside it;

[0068] A central rod 53 is coaxially arranged inside the shaft tube 52, and the upper end of the central rod 53 is fixed to the rotating hinge shaft 42;

[0069] The hydraulic chamber 54 is centrally located within the guide cylinder 51, and the lower end of the central rod 53 is slidably connected to the hydraulic chamber 54 via a piston seal.

[0070] The hydraulic channel 55 is opened inside the guide cylinder 51, and one end of it is sealed and connected to the hydraulic chamber 54. In this way, the hydraulic channel 55 is used to adjust the hydraulic pressure inside the hydraulic chamber 54 during the extension and retraction adjustment of the fine adjustment controller 5, thereby realizing the axial fine adjustment of the center rod 53.

[0071] In this embodiment, the shaft tube 52 is fitted with an outer support spring 56, the inner wall of the guide cylinder 51 is provided with a flange, the lower end of the outer support spring 56 is connected to the flange, and its upper end is connected to the end of the central rod 53.

[0072] The guide cylinder 51 has multiple sliding cavities 57 on its inner circumference. Each sliding cavity 57 is slidably connected to a support rod 58. The upper end of each support rod 58 is connected to a compression spring 59. The upper end of each compression spring 59 is connected to the shaft tube 52. Each sliding cavity 57 is connected to an air pressure pipe for adjusting the air pressure inside the sliding cavity 57. The air pressure of each sliding cavity 57 can be adjusted independently, so that the compression spring 59 is compressed in different forms. In this way, multiple compression springs 59 can cooperate to form multi-stage shock absorption. It should be noted that when the fine adjustment controller 5 is elastically floating under the moving platform, the hydraulic channel 55 is in the conducting state, and the center rod 53 can be freely axially slidably adjusted, thereby automatically compensating for geometric errors and assembly errors, and effectively eliminating internal mechanical stress.

[0073] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A self-balancing, over-constrained six-degree-of-freedom parallel platform, characterized in that, It includes: A fixed platform (1) has multiple connecting sub-plates (11) distributed around its upper end face. The moving platform (12) is located above the fixed platform (1), and the lower end face of the moving platform (12) is provided with multiple connecting sub-plates. The drive rod (3) is configured as multiple, and each of the connecting sub-plate 1 (11) and connecting sub-plate 2 is provided with two universal hinge shafts (13). The lower end of each drive rod (3) is connected to the universal hinge shaft (13) on the connecting sub-plate 1 (11); A fine-tuning slave (4) is set on the output end of each drive rod (3). The upper end of the drive rod (3) is connected to the universal hinge shaft (13) on the connecting sub-plate (11) through the fine-tuning slave (4). The attitude detection unit (2) is installed on the lower end face of the moving platform (12).

2. The self-balancing, over-constrained six-degree-of-freedom parallel platform according to claim 1, characterized in that: The two drive rods (3) on the connecting subplate (11) are arranged in a V-shape.

3. The self-balancing, over-constrained six-degree-of-freedom parallel platform according to claim 1, characterized in that, The attitude detection unit (2) includes: The slide rail brackets (21) are configured as three and distributed in a circular pattern on the lower end face of the moving platform (12); The distance measuring sensor (22) is set one-to-one with the slide rail frame (21). The slide rail frame (21) is slidably mounted with a transfer block. The distance measuring sensor (22) is installed below the transfer block. A rotating disk (23) is rotatably mounted on a moving platform (12). The rotating disk (23) has multiple inclined slots (24). A guide pin is vertically fixed on the transfer block. One end of the guide pin is slidably connected in the inclined slot (24).

4. A self-balancing, over-constrained six-degree-of-freedom parallel platform according to claim 3, characterized in that: Each of the distance measuring sensors (22) is always vertically oriented towards the fixed platform (1); The lower end face of the moving platform (12) is equipped with a control motor for driving the rotating disk (23) to rotate.

5. A self-balancing, over-constrained six-degree-of-freedom parallel platform according to claim 1, characterized in that, The fine-tuning slave (4) includes: The upper end face of the sliding shaft plate (41) is fixed to the universal hinge shaft (13), and two sliders are symmetrically slidably arranged inside the sliding shaft plate (41). There are two fine adjustment controllers (5). Each fine adjustment controller (5) is connected to a rotating hinge shaft (42) at its upper and lower ends. The rotating hinge shaft (42) at the lower end of the fine adjustment controller (5) is connected to the shaft (31) in the drive rod (3), and the rotating hinge shaft (42) at the upper end of the fine adjustment controller (5) is connected to the slider in the slide plate (41).

6. A self-balancing, over-constrained six-degree-of-freedom parallel platform according to claim 5, characterized in that: A guide shaft (43) is fixed in the middle of the sliding plate (41), and a linkage rod (44) is rotatably connected to the guide shaft (43). Guide grooves (45) are symmetrically opened at both ends of the linkage rod (44). A guide pin is fixed on each slider, and the guide pin is slidably connected to the guide groove (45). Two inner springs are symmetrically connected inside the slide plate (41), and the other end of the inner spring is connected to the slider.

7. A self-balancing, over-constrained six-degree-of-freedom parallel platform according to claim 6, characterized in that: A fixed tube (32) is coaxially slidably sleeved on the outside of the shaft (31). A limit ring is fixed at the upper end of the inside of the fixed tube (32). An inner hole corresponding to the fine adjustment controller (5) is opened in the limit ring. The limit ring is slidably sleeved on the outside of the fine adjustment controller (5) through the inner hole. The lower end of the shaft (31) is coaxially sealed with a pressure ring (33), and the lower end of the fixed tube (32) is slidably connected to the pressure ring (33). An L-shaped channel (34) is opened inside the shaft (31). One end of the L-shaped channel (34) is connected to the pressure ring (33), and the other end is connected to a duct hose (35). A duct seat (36) is fixed inside the lower part of the drive rod (31), and the duct hose (35) is connected to the duct seat (36).

8. A self-balancing, over-constrained six-degree-of-freedom parallel platform according to claim 7, characterized in that: When the limiting ring slides downward with the fixed tube (32) and slides away from the fine adjustment controller (5), the two sliders slide in opposite directions under the pull of the inner spring, so that the two fine adjustment controllers (5) are set up in a V shape.

9. A self-balancing, over-constrained six-degree-of-freedom parallel platform according to claim 5, characterized in that, The fine-tuning controller (5) includes: The guide cylinder (51) has a shaft tube (52) that is slidably connected to it internally. A central rod (53) is coaxially arranged inside the shaft tube (52), and the upper end of the central rod (53) is fixed to the rotating hinge shaft (42); The hydraulic chamber (54) is centrally located inside the guide cylinder (51), and the lower end of the central rod (53) is slidably connected to the hydraulic chamber (54) through a piston seal. A hydraulic channel (55) is provided inside the guide cylinder (51), and one end of it is sealed and connected to the hydraulic chamber (54).

10. A self-balancing, over-constrained six-degree-of-freedom parallel platform according to claim 9, characterized in that: The shaft tube (52) is fitted with an outer support spring (56), the inner wall of the guide cylinder (51) is provided with a flange, the lower end of the outer support spring (56) is connected to the flange, and its upper end is connected to the end of the central rod (53). The guide cylinder (51) has multiple sliding cavities (57) on its inner circumference. Each sliding cavity (57) is slidably connected to a support rod (58). The upper end of each support rod (58) is connected to a compression spring (59). The upper end of the compression spring (59) is connected to the shaft tube (52).

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