Self-adaptive flexible positioning and posture adjusting tool and method

Abstract

The invention relates to a self-adaptive flexible positioning and posture adjusting tool and method, and belongs to the technical field of tool jigs, and the self-adaptive flexible positioning and posture adjusting tool comprises a positioning and posture adjusting unit which is used for sequentially carrying out fitting positioning on the middle part and the end part of a workpiece or the end part and the middle part of the workpiece; and the adjusting unit is used for adjusting the heights of the positioning and posture adjusting unit and the workpieces on the positioning and posture adjusting unit. The positioning and posture adjusting unit comprises a suction cup assembly base, and a plurality of flexible suction cup assemblies are independently installed on the suction cup assembly base and used for positioning and posture adjusting of workpieces. The adjusting unit comprises a plurality of electric cylinders, and floating connectors are arranged between the electric cylinders and the positioning and posture adjusting unit and used for absorbing eccentric deflection angles between piston rods of the electric cylinders and the positioning and posture adjusting unit. High-precision and high-stability positioning and posture adjusting functions of the large-size curved surface workpiece can be achieved, numerical control machine tool or robot machining equipment is perfected, and the machining automation level of the numerical control machine tool or robot and the overall machining precision of the equipment are improved.

Description

Technical Field

[0001] This invention belongs to the field of tooling and fixture technology, and particularly relates to an adaptive flexible positioning and orientation adjustment tooling and method. Background Technology

[0002] Large curved surface workpieces are characterized by their large size, heavy weight, high requirements for dimensional and surface accuracy, complex curvature of the working surface, and stringent requirements for high-order continuity. Their surface roughness needs to meet high standards. Manual grinding methods are difficult to balance processing quality and time. However, CNC machine tools or industrial robots, with their good flexibility, can achieve multi-body posture processing, making automated high-precision polishing of complex curved surfaces a cutting-edge interdisciplinary field of modern precision machining and automated manufacturing. Using such equipment for processing large curved surface workpieces is the preferred solution.

[0003] Positioning and orientation adjustment fixtures for curved parts are key supporting devices for ensuring high-precision machining of CNC machine tools or industrial robots. However, there are still significant shortcomings in positioning and orientation adjustment: on the one hand, there are very few technologies in existing devices that involve flexible positioning of curved workpieces, especially for large-sized curved workpieces, which cannot achieve multi-point contact adaptive positioning, resulting in poor workpiece positioning stability and insufficient positioning accuracy, directly affecting the accuracy of subsequent machining references; on the other hand, there is a lack of relevant records on orientation adjustment fixtures for curved workpieces in existing technologies, making it difficult for the tool end to fully contact the curved surface of the workpiece during machining, resulting in uneven machining removal and failing to guarantee the machining effect and surface accuracy requirements.

[0004] Therefore, existing positioning and orientation adjustment tooling technologies cannot meet the supporting requirements for automated high-precision grinding and polishing of large-sized curved surface workpieces. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides an adaptive flexible positioning and orientation adjustment fixture and method, which enables high-precision and high-stability positioning and orientation adjustment of large-sized curved workpieces, improves CNC machine tools or robot processing equipment, and enhances the automation level and overall processing accuracy of CNC machine tools or robot processing.

[0006] An adaptive flexible positioning and attitude adjustment fixture, comprising:

[0007] The positioning and posture adjustment unit performs sequential fitting and positioning of the middle part and the end part of the workpiece, or the end part and the middle part.

[0008] The adjustment unit is used to adjust the height of the positioning and orientation unit and the workpiece on it.

[0009] The positioning and orientation adjustment unit includes a suction cup assembly base, on which multiple flexible suction cup assemblies are independently mounted for positioning and orientation adjustment of the workpiece.

[0010] The flexible suction cup assembly includes a cylinder mounting base, with the fixed end of the lifting cylinder mounted on the cylinder mounting base and the suction cup mounted on the movable end of the lifting cylinder.

[0011] The movable end of the lifting cylinder is equipped with a clamping plate, which has a cantilever structure at the movable end of the lifting cylinder. A motion shaft is installed at the cantilever end of the clamping plate, and a suction cup is installed in the motion shaft. When the lifting cylinder extends upward or retracts downward, it drives the clamping plate, the motion shaft on the clamping plate, and the suction cup on the motion shaft to move up and down in the vertical direction simultaneously through the movable end, so as to achieve contact with the workpiece.

[0012] A force sensor is installed between the suction cup and the motion axis to provide feedback on the contact status between the suction cup and the workpiece surface.

[0013] The positioning and attitude adjustment unit also includes a locking mechanism to lock the position of the lifting cylinder and ensure the stability of the workpiece.

[0014] The locking mechanism includes a locking cylinder mounted on a cylinder block mounting base. A notch is provided axially on the motion shaft for engaging with the locking cylinder to achieve locking.

[0015] The adjustment unit includes multiple electric cylinders.

[0016] A floating joint is provided between the electric cylinder and the positioning and attitude adjustment unit to absorb the eccentricity angle between the piston rod of the electric cylinder and the positioning and attitude adjustment unit, thereby preventing the piston rod of the electric cylinder from bending and failing.

[0017] An adaptive flexible positioning and attitude adjustment method, using the aforementioned adaptive flexible positioning and attitude adjustment fixture, specifically includes the following steps:

[0018] First, attach the workpiece to the workpiece positioning and orientation adjustment unit, focusing on the position on the workpiece that is closest to the unit.

[0019] Adjust the positioning and attitude adjustment units that are not in contact with the workpiece to ensure full contact with the workpiece;

[0020] Start the adjustment unit and adjust the workpiece height as needed.

[0021] By employing the above technical solution, the present invention has at least the following beneficial effects:

[0022] This invention incorporates a flexible suction cup assembly. Through the independent single-point adsorption and multi-point collaborative adsorption of the flexible suction cup assembly, combined with the feedback control of the lifting cylinder by the force sensor, it can provide passive flexibility for the complex curvature of large-sized curved workpieces, achieving multi-point adaptive positioning. This solves the problems of poor positioning stability and inability to adapt to curved surface shapes in traditional tooling.

[0023] This invention provides a structural design that combines multiple electric cylinders with a floating joint. The coordinated drive of the multiple electric cylinders and the eccentric angle design of the floating joint can precisely adjust the spatial height and tilt posture of the workpiece, ensuring accurate adaptation of the workpiece machining reference to the machine tool or robot machining path, and improving machining and posture adjustment efficiency.

[0024] This invention features a design that integrates a locking cylinder with a notch in the motion shaft. After the flexible suction cup assembly makes full contact with the workpiece, it achieves rigid locking, effectively resisting the influence of external processing forces and the workpiece's own weight, and ensuring the stability of the workpiece's position during processing.

[0025] In addition to being applicable to the front and back positioning of large curved workpieces, this invention is also compatible with the positioning and orientation adjustment needs of various workpieces such as large thin plate workpieces and workpieces with holes in the middle. It is applicable to workpieces of different weights and can achieve multi-scenario processing adaptation through a set of tooling, reducing equipment investment costs and changeover and debugging time. Attached Figure Description

[0026] Figure 1 This is a front view of the adaptive flexible positioning and attitude adjustment fixture provided by the present invention.

[0027] Figure 2 A perspective view of the adaptive flexible positioning and attitude adjustment fixture provided by the present invention;

[0028] Figure 3 A schematic diagram of the flexible suction cup assembly in the adaptive flexible positioning and attitude adjustment tooling provided by the present invention;

[0029] Figure 4 This is a schematic diagram of the front of a workpiece with a load-bearing curved surface, using the adaptive flexible positioning and attitude adjustment fixture provided by this invention.

[0030] Figure 5 This is a schematic diagram of the reverse side of a workpiece subjected to a load using the adaptive flexible positioning and attitude adjustment fixture provided by this invention.

[0031] Figure 6 This is a schematic diagram of the initial state of a thin plate workpiece under load using the adaptive flexible positioning and attitude adjustment tooling provided by the present invention.

[0032] Figure 7 This is a schematic diagram illustrating the working state of a thin-plate workpiece under load using the adaptive flexible positioning and attitude adjustment fixture provided by this invention.

[0033] in:

[0034] 1-Workbench, 2-Electric cylinder, 3-Floating joint, 4-Suction cup assembly base, 5-Lifting cylinder, 6-Clamping plate, 7-Motion axis, 8-Force sensor, 9-Suction cup, 10-Locking cylinder. Detailed Implementation

[0035] To better explain and facilitate understanding of the present invention, the technical solution and effects of the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0036] like Figures 1-2 As shown, an adaptive flexible positioning and attitude adjustment fixture includes a worktable 1 at the bottom, which serves as a basic load-bearing part for mounting and fixing a positioning and attitude adjustment unit; the positioning and attitude adjustment unit includes a suction cup assembly base 4, which is positioned above the worktable 1 by multiple electric cylinders 2, which are used to change the height of the suction cup assembly base 4; multiple flexible suction cup assemblies are mounted on the suction cup assembly base 4 for positioning and attitude adjustment of large curved workpieces.

[0037] The worktable 1 is a horizontally positioned support base at the bottom, specifically a rigid frame structure. Four electric cylinders 2 are mounted on the top surface of the worktable 1 in a 2×2 matrix arrangement, serving as the four support corners of the suction cup assembly base 4. Equipped with multiple servo motors, each electric cylinder 2 can travel any distance. By adjusting different electric cylinders 2, a multi-degree-of-freedom attitude adjustment unit combining three active and one passive components is formed. The output shafts of the electric cylinders 2 extend vertically upwards, and the top ends of the output shafts of all electric cylinders 2 are fixedly connected to a horizontally arranged suction cup assembly base 4. Each electric cylinder 2 can independently achieve telescopic drive. Through the coordinated action of multiple electric cylinders 2, the spatial height and tilt posture of the suction cup assembly base 4 are precisely adjusted, thus providing basic support for subsequent workpiece positioning and attitude adjustment. The suction cup assembly base 4 has multiple mounting holes, each corresponding to a flexible suction cup assembly 3. Each vacuum suction cup is connected to an external vacuum generator through an independent air passage, enabling single-point independent adsorption or multi-point coordinated adsorption according to the workpiece's curved surface shape. Through the precise drive adjustment of the multi-cylinder 2 and the adaptive adsorption of the flexible suction cup assembly 3, this tooling can achieve multi-point flexible positioning for the complex curvature characteristics of large curved workpieces. At the same time, the spatial posture of the workpiece is adjusted by the coordinated action of the electric cylinder 2, ensuring that the workpiece processing datum is accurately matched with the processing path of the CNC machine tool or industrial robot, effectively solving the problems of unstable positioning and insufficient posture adjustment accuracy of large curved workpieces.

[0038] Furthermore, a floating joint 3 is provided between the movable end of the electric cylinder 2 and the suction cup assembly base 4. One end of the floating joint 3 is connected to the electric cylinder 2, and the other end is connected to the suction cup assembly base 4. When several of the electric cylinders 2 are raised, the angle between the piston rod of the electric cylinder 2 and the suction cup assembly base 4 is no longer perpendicular. The floating joint 3 is used to absorb the eccentricity angle between the piston rod of the electric cylinder 2 and the suction cup assembly base 4, so as to prevent the piston rod of the electric cylinder 2 from bending and failing.

[0039] like Figure 3 As shown, the suction cup assembly base 4 includes a cylinder fixing seat, on which a lifting cylinder 5 is mounted. The fixed end of the lifting cylinder 5 is mounted on the cylinder fixing seat, and one end of the clamping plate 6 is mounted on the movable end of the lifting cylinder 5, forming a cantilever structure. A motion shaft is mounted on the cantilever end of the clamping plate 6, and the suction cup 9 is mounted in the motion shaft 7. The lifting cylinder 5 extends upward or retracts downward, driving the clamping plate, the motion shaft on the clamping plate, and the suction cup on the motion shaft to move up and down simultaneously in the vertical direction through the movable end, thereby achieving contact with the workpiece. Furthermore, a force sensor is set between the suction cup 9 and the motion shaft. The force sensor 8 provides feedback on the contact status between the suction cup 9 and the workpiece surface, ensuring that each suction cup 9 is adsorbed on the workpiece surface.

[0040] The suction cup 9 is installed on top of the force sensor 8. The lifting cylinder 5 moves the suction cup 9 so that each suction cup 9 is in full contact with the surface of the workpiece, thereby improving the suction force of the suction cup 9 on the workpiece and ensuring the stability of the workpiece during processing.

[0041] Furthermore, the motion shaft 7 has an axial notch for fixing the suction cup position. Simultaneously, a locking cylinder 10 is mounted on the cylinder mounting base to engage with the notch on the motion shaft for locking. In this embodiment, the lifting cylinder 5 and the locking cylinder 10 are mounted opposite each other. The front end of the locking cylinder 10 is provided with a conical locking element (not shown in the figure). When the lifting cylinder 5 is activated and the motion shaft 7 stops working, the locking cylinder 10 starts working, and the conical locking element contacts the notch on the motion shaft 7 to hold the motion shaft 7 in place. The notch on the motion shaft 7 is used for fixing, preventing the motion shaft 7 from moving up and down, achieving the locking purpose and ensuring overall stability.

[0042] When the workpiece is placed on the suction cup assembly, due to the curved surface of the workpiece, only a portion of its area contacts the suction cup. At this time, the lifting cylinder 5 is ventilated, driving the motion shaft 7 and suction cup 9 upwards via the clamping plate 6. This ensures that each suction cup assembly fully contacts the workpiece surface, achieving multi-point contact and adaptive flexible positioning. Furthermore, because the large curved workpiece is relatively heavy, the lifting cylinder 5 will not push the workpiece, ensuring accurate workpiece positioning.

[0043] Example 1

[0044] like Figure 4As shown, the aforementioned adaptive flexible positioning and attitude adjustment fixture is used to perform adaptive flexible positioning and attitude adjustment on the front of a large curved workpiece. When the front of the large curved workpiece is placed on the flexible suction cup assembly, due to the different curvatures of the workpiece itself, the flexible suction cup assembly in the middle will preferentially contact the workpiece surface, while the flexible suction cup assemblies on both sides will not contact the workpiece. At this time, based on the feedback from the force sensor 8, the lifting cylinder 5 corresponding to the flexible suction cup assembly is controlled to ventilate for the non-contacting flexible suction cup assembly, which drives the motion shaft 7 and suction cup 9 to move upward through the clamping plate 6, so that each flexible suction cup assembly fully contacts the workpiece surface. Then, the locking cylinder 10 works, using the notch of the motion shaft 7 to fix the flexible suction cup assembly. Finally, the electric cylinder 2, driven by the servo motor, drives the floating joint 3 to move, adjusting the processing posture of the large curved workpiece.

[0045] Example 2

[0046] like Figure 5 As shown, the aforementioned adaptive flexible positioning and attitude adjustment fixture is used to perform adaptive flexible positioning and attitude adjustment on the reverse side of a large curved workpiece. When the reverse side of the large curved workpiece is placed on the flexible suction cup assembly, due to the different curvatures of the workpiece itself, the flexible suction cup assemblies at both ends will preferentially contact the workpiece surface, while the flexible suction cup assemblies in the middle will not contact the workpiece. At this time, based on the feedback from the force sensor 8, the lifting cylinder 5 corresponding to the flexible suction cup assembly is controlled to ventilate for the uncontacted flexible suction cup assemblies. This drives the motion shaft 7 and suction cup 9 to move upward through the clamping plate 6, ensuring that each flexible suction cup assembly fully contacts the workpiece surface. Then, the locking cylinder 10 operates, using the notch of the motion shaft 7 to fix the flexible suction cup assembly. Finally, the electric cylinder 2, driven by the servo motor, drives the floating joint 3 to move, adjusting the processing posture of the large curved workpiece.

[0047] Example 3

[0048] like Figure 6 As shown, the aforementioned adaptive flexible positioning and attitude adjustment fixture is used to perform adaptive flexible positioning and attitude adjustment on a large-sized thin plate workpiece. When the workpiece is placed on the suction cup assembly, due to the warping of the short side of the thin plate workpiece, the flexible suction cup assembly in the middle will preferentially contact the workpiece surface, while the flexible suction cup assemblies on both sides will not make contact. At this time, based on the feedback from the force sensor 8, the corresponding lifting cylinder 5 is controlled to ventilate for the uncontacted suction cup assemblies, driving the motion shaft 7 and suction cup 9 upward through the clamping plate 6, so that each suction cup assembly fully contacts the workpiece surface. At this time, all flexible suction cup assemblies are in contact with the workpiece surface. Then, all lifting cylinders 5 are controlled to descend to the initial position, as shown. Figure 7As shown. When the locking cylinder 10 is in operation, the flexible suction cup assembly is fixed by the notch of the motion shaft 7, so that all suction cup assemblies are on the same horizontal plane. This can temporarily eliminate the problem of plate warping and ensure that the large-size thin plate is in a better flatness state, which is convenient for subsequent workpiece surface grinding.

[0049] The adaptive flexible positioning and attitude adjustment fixture provided by the present invention can complete the adaptive flexible positioning and attitude adjustment of the front and back sides of large curved workpieces and thin plate workpieces. The fixture can adapt to workpiece processing in multiple scenarios.

Claims

1. An adaptive flexible positioning and attitude adjustment fixture, characterized in that, include: The positioning and posture adjustment unit performs sequential fitting and positioning of the middle part and the end part of the workpiece, or the end part and the middle part. The adjustment unit is used to adjust the height of the positioning and orientation unit and the workpiece on it.

2. The adaptive flexible positioning and attitude adjustment fixture according to claim 1, characterized in that: The positioning and orientation adjustment unit includes a suction cup assembly base, on which multiple flexible suction cup assemblies are independently mounted for positioning and orientation adjustment of the workpiece.

3. The adaptive flexible positioning and attitude adjustment fixture according to claim 2, characterized in that: The flexible suction cup assembly includes a cylinder mounting base, with the fixed end of the lifting cylinder mounted on the cylinder mounting base and the suction cup mounted on the movable end of the lifting cylinder.

4. The adaptive flexible positioning and attitude adjustment fixture according to claim 3, characterized in that: The movable end of the lifting cylinder is equipped with a clamping plate, which has a cantilever structure at the movable end of the lifting cylinder. A motion shaft is installed at the cantilever end of the clamping plate, and a suction cup is installed in the motion shaft. When the lifting cylinder extends upward or retracts downward, it drives the clamping plate, the motion shaft on the clamping plate, and the suction cup on the motion shaft to move up and down in the vertical direction simultaneously through the movable end, so as to achieve contact with the workpiece.

5. The adaptive flexible positioning and attitude adjustment fixture according to claim 4, characterized in that: A force sensor is installed between the suction cup and the motion axis to provide feedback on the contact status between the suction cup and the workpiece surface.

6. The adaptive flexible positioning and attitude adjustment fixture according to claim 4, characterized in that: The positioning and attitude adjustment unit also includes a locking mechanism to lock the position of the lifting cylinder and ensure the stability of the workpiece.

7. The adaptive flexible positioning and attitude adjustment fixture according to claim 6, characterized in that: The locking mechanism includes a locking cylinder mounted on a cylinder block mounting base. A notch is provided axially on the motion shaft for engaging with the locking cylinder to achieve locking.

8. The adaptive flexible positioning and attitude adjustment fixture according to claim 1, characterized in that: The adjustment unit includes multiple electric cylinders.

9. The adaptive flexible positioning and attitude adjustment fixture according to claim 8, characterized in that: A floating joint is provided between the electric cylinder and the positioning and attitude adjustment unit to absorb the eccentricity angle between the piston rod of the electric cylinder and the positioning and attitude adjustment unit, thereby preventing the piston rod of the electric cylinder from bending and failing.

10. An adaptive flexible positioning and attitude adjustment method, using the adaptive flexible positioning and attitude adjustment fixture described in any one of claims 1 to 9, characterized in that, Specifically, the following steps are included: First, attach the workpiece to the workpiece positioning and orientation adjustment unit, focusing on the position on the workpiece that is closest to the unit. Adjust the positioning and attitude adjustment units that are not in contact with the workpiece to ensure full contact with the workpiece; Start the adjustment unit and adjust the workpiece height as needed.

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