High-precision low-wear six-degree-of-freedom platform

Abstract

The invention discloses a high-precision low-abrasion six-degree-of-freedom platform, and relates to the technical field of six-degree-of-freedom platforms, the high-precision low-abrasion six-degree-of-freedom platform comprises an experiment table, a top platform, a movable rod and a servo electric cylinder, a flexible hooke joint is connected between the movable rod and the top platform, and the flexible hooke joint comprises two flexible connecting blocks; the interiors of the two flexible connecting blocks are connected with upper pin shafts through upper bearings. Through the arrangement of a displacement detector and a flexible hooke joint, a telescopic rod can drive a reading head to move while stretching out and drawing back, at the moment, macro movement of a top platform is measured and fed back through the reading head corresponding to a magnetic railing ruler, but due to the fact that friction exists in the structure, the displacement fed back by the reading head in cooperation with the magnetic railing ruler is not the actual displacement of the top platform; therefore, friction on a traditional rigid hooke joint and a telescopic rod is converted into elastic deformation of the flexible hooke joint, the deformation amount of the flexible connecting block is detected through the strain gauge, and the influence caused by friction force of all parts is isolated. And the driving and transmission efficiency is improved.

Description

Technical Field

[0001] The invention relates to the technical field of six-degree-of-freedom platforms, in particular to a high-precision, low-wear six-degree-of-freedom platform. Background Art

[0002] The Stewart platform refers to a six-degree-of-freedom motion platform with retractable legs. The platform can be quickly adjusted according to actual needs, thereby achieving precise control of the load. In terms of structure, the Stewart platform adopts a parallel mechanism design, which has less error accumulation than a series mechanism and therefore has higher precision. In addition, the platform also adopts a symmetrical structure, which makes it is isotropic and further improves its motion performance. Because the six-degree-of-freedom Stewart platform has high rigidity, strong load-bearing capacity, high positioning accuracy and full freedom in all directions in space, it is widely used in large-scale simulation test equipment such as vehicle motion simulation, ship platform simulators, aircraft and spacecraft, and precision manufacturing systems.

[0003] Although the positioning accuracy of the traditional Stewart platform has been improved through some advanced algorithms and precise modeling methods, it is inevitable that deviations will occur during positioning operations, resulting in unsatisfactory positioning results. For example: 1) During the movement process, the Stewart platform will produce three frictions: the Hooke's hinge between the fixed platform and the actuator, the actuator itself, and the Hooke's hinge between the actuator and the moving platform; the accumulated errors of these three parts of friction limit the improvement of the platform's accuracy, which further leads to certain errors in the measurement results; 2) In a vibrating environment, the connection stability between the actuator and the moving platform will be greatly reduced, resulting in a reduction in the positioning accuracy of the system; 3) During the movement process, the existence of friction will cause certain wear on the internal structure of the Stewart platform, thereby affecting its service life. Therefore, in order to effectively solve the above problems, a flexible Hooke's hinge and a high-precision Stewart platform using it were invented, which can effectively improve the positioning accuracy of the system and isolate the positioning effects caused by friction. Summary of the invention

[0004] Based on this, the purpose of the present invention is to provide a high-precision, low-wear six-degree-of-freedom platform to solve the technical problems mentioned in the above background technology.

[0005] To achieve the above-mentioned purpose, the present invention provides the following technical solutions: a high-precision, low-wear six-degree-of-freedom platform, comprising a laboratory table, a top platform, a moving rod, a servo electric cylinder and a displacement detector, a flexible Hooke's hinge is connected between the moving rod and the top platform, and the flexible Hooke's hinge comprises two flexible connecting blocks, both of which are connected to upper pins through upper bearings, and an upper universal joint connecting block is connected between the two upper pins; the displacement detector comprises a strain gauge, a reading head is installed on the outer surface of the moving rod, and a magnetic scale is connected to one side of the servo electric cylinder.

[0006] By adopting the above technical solution, a telescopic rod will drive the displacement of the reading head while extending and retracting. At this time, the reading head corresponds to the magnetic scale to measure and feedback the macro movement of the top platform. However, due to the friction in the structure, the displacement of the reading head in conjunction with the magnetic scale is not the actual displacement of the top platform. Therefore, the friction on the traditional rigid Hooke's joint and the telescopic rod is converted into the elastic deformation of the flexible Hooke's joint, and the deformation of the flexible connecting block is detected by the strain gauge, which isolates the influence of the friction force of each part, facilitates energy storage and conversion, and realizes accurate friction compensation. Combined with the displacement feedback of the magnetic scale and the reading head, the precise positioning of the platform is finally achieved.

[0007] Furthermore, the flexible connection block is made of POM plastic, spring steel or stainless steel, and a plurality of through holes are formed on one side of the flexible connection block.

[0008] By adopting the above technical solution, since a plurality of through holes are opened on the side of the flexible connection block, the flexible connection block is relatively weak, and a more obvious elastic deformation can be produced under the action of torque, thereby converting the friction on the traditional rigid Hooke's joint and the telescopic rod into the elastic deformation of the flexible Hooke's joint, isolating the influence of the friction force of each part, facilitating energy storage and conversion, and realizing accurate friction compensation.

[0009] Furthermore, the upper universal joint connection block is rotatably connected to the flexible connection block via an upper bearing and an upper pin shaft.

[0010] By adopting the above technical solution, the two flexible connection blocks are connected by the upper universal joint connection block, so that the telescopic rod can move and rotate in three directions of XYZ to support the six free angles of the top platform.

[0011] Furthermore, the top of the experimental table is connected to a base, and the top of the base is connected to a rigid Hooke's hinge, the top of the rigid Hooke's hinge is connected to a telescopic rod, and the top of the telescopic rod is connected to a top platform through a flexible Hooke's hinge.

[0012] By adopting the above technical solution, after the telescopic rod is started, it drives one corner of the top platform to move up or down. At the same time, the telescopic rod and the top platform are adapted to rotate through the flexible Hooke's joint and the rigid Hooke's joint, thereby realizing six degrees of freedom movement of the top platform.

[0013] Furthermore, the rigid Hooke's joint includes a rigid connection block connected to the top of the base and to the bottom of the telescopic rod, and the two rigid connection blocks are internally connected to lower pins through lower bearings, and a lower universal joint connection block is connected between the two lower pins.

[0014] By adopting the above technical solution, the two rigid connection blocks are connected through the lower universal joint connection block, so that the telescopic rod can move and rotate in three directions of XYZ to support six free angles of the top platform.

[0015] Furthermore, the lower universal joint connection block is rotatably connected to the rigid connection block via a lower bearing and a lower pin shaft.

[0016] By adopting the above technical solution, the telescopic rod can move and rotate in three directions of XYZ when rotating, thereby realizing six degrees of freedom movement.

[0017] Furthermore, the telescopic rod includes a fixed rod installed on the top of the rigid Hooke's joint, and a servo electric cylinder is installed outside the fixed rod, and a moving rod is connected to the top of the fixed rod.

[0018] By adopting the above technical solution, the servo electric cylinder converts the rotary motion into linear motion after being started, so that the moving rod extends from the top rod, thereby driving a corner of the top platform to move up or down.

[0019] Furthermore, the telescopic rod is one of an electric cylinder, a pneumatic cylinder and a hydraulic cylinder.

[0020] By adopting the above technical solution, the electric cylinder type telescopic rod can be changed into a hydraulic type or a pneumatic type telescopic rod according to different working conditions and working environments.

[0021] Furthermore, six of the rigid Hooke's joints, telescopic rods and flexible Hooke's joints are provided, two in a group, and divided into three groups in total, and the three groups of rigid Hooke's joints, telescopic rods and flexible Hooke's joints are distributed in a ring array.

[0022] By adopting the above technical solution, six electric cylinder telescopic rods composed of fixed rods, moving rods and servo electric cylinders can perform independent telescopic movements to adjust the heights of the three corners of the top platform.

[0023] Furthermore, the top end of the telescopic rod is rotatably connected to the top platform via a flexible Hooke's joint, and the bottom end of the telescopic rod is rotatably connected to the base via a rigid Hooke's joint.

[0024] By adopting the above technical solution, six electric cylinder telescopic rods composed of fixed rods, moving rods and servo electric cylinders can perform independent telescopic movements, and rigid Hooke's joints and flexible Hooke's joints are used to enable the telescopic rods to rotate with the base and the top platform, thereby realizing six degrees of freedom movement of the top platform.

[0025] In summary, the present invention mainly has the following beneficial effects:

[0026] The present invention arranges a displacement detector and a flexible Hooke's joint. When a telescopic rod is extended or retracted, the telescopic rod drives the reading head to move. At this time, the reading head measures and feeds back the macro movement of the top platform corresponding to the magnetic scale. However, due to the friction in the structure, the displacement fed back by the reading head in cooperation with the magnetic scale is not the actual displacement of the top platform. Therefore, the friction on the traditional rigid Hooke's joint and the telescopic rod is converted into the elastic deformation of the flexible Hooke's joint, and the deformation of the flexible connecting block is detected by a strain gauge, thereby isolating the influence of the friction force of each part, facilitating energy storage and conversion, thereby realizing accurate friction compensation, and combining the displacement feedback of the magnetic scale and the reading head to finally realize accurate positioning of the platform and improve the driving and transmission efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a structural schematic diagram of the present invention;

[0028] Figure 2 It is a schematic diagram of the rigid Hooke's hinge structure of the present invention;

[0029] Figure 3 It is a schematic diagram of the telescopic rod structure of the present invention;

[0030] Figure 4 It is a schematic diagram of the flexible Hooke's hinge structure of the present invention;

[0031] Figure 5 Schematic diagram of the installation position of the strain gauge of the present invention;

[0032] Figure 6 It is a schematic diagram of the structure of the flexible connection block of the present invention.

[0033] In the figure: 1. experimental table; 2. base; 3. rigid Hooke's hinge; 301. rigid connection block; 302. lower bearing; 303. lower pin shaft; 304. lower universal joint connection block; 4. telescopic rod; 401. fixed rod; 402. moving rod; 403. servo electric cylinder; 5. displacement detector; 501. magnetic scale; 502. reading head; 503. strain gauge; 6. flexible Hooke's hinge; 601. flexible connection block; 602. upper bearing; 603. upper pin shaft; 604. upper universal joint connection block; 7. top platform. DETAILED DESCRIPTION

[0034] The following will be combined with the accompanying drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0035] The following describes an embodiment of the present invention based on its overall structure.

[0036] Embodiment 1:

[0037] A high-precision, low-wear six-degree-of-freedom platform, such as Figure 1 , Figure 4 , Figure 5 and Figure 6 As shown, it includes a test bench 1, a top platform 7, a moving rod 402, a servo electric cylinder 403 and a displacement detector 5. A flexible Hooke's hinge 6 is connected between the moving rod 402 and the top platform 7. The flexible Hooke's hinge 6 includes two flexible connection blocks 601. The flexible connection block 601 is made of POM plastic, spring steel or stainless steel. A plurality of through holes are provided on one side of the flexible connection block 601. The flexible connection block 601 is relatively weak and can produce obvious elastic deformation under the action of torque, thereby converting the friction on the traditional rigid Hooke's hinge 3 and the telescopic rod 4 into the elastic deformation of the flexible Hooke's hinge 6; the two flexible connection blocks 601 are connected to the upper pin 603 through the upper bearing 602. The two upper pins An upper universal joint connection block 604 is connected between 603, and the upper universal joint connection block 604 is rotatably connected to the flexible connection block 601 through an upper bearing 602 and an upper pin shaft 603, and can support the movement and rotation of the telescopic rod 4 and the top platform 7 in three directions of XYZ; the displacement detector 5 includes a strain gauge 503, and the deformation of the flexible connection block 601 is detected by the strain gauge 503; a reading head 502 is installed on the outer surface of the moving rod 402, and a magnetic scale 501 is connected to one side of the servo electric cylinder 403, and the macro movement of the top platform 7 is measured and fed back by the reading head 502 corresponding to the magnetic scale 501.

[0038] See also Figure 1-Figure 3In the above embodiment, the top of the experimental table 1 is connected to the base 2, and the top of the base 2 is connected to the rigid Hooke's hinge 3, the rigid Hooke's hinge 3 includes a rigid connection block 301 connected to the top of the base 2 and connected to the bottom of the telescopic rod 4, the two rigid connection blocks 301 are connected to the lower pin 303 through the lower bearing 302, and the lower universal joint connection block 304 is connected between the two lower pins 303, and the lower universal joint connection block 304 is rotatably connected to the rigid connection block 301 through the lower bearing 302 and the lower pin 303, which can support the movement and rotation of the telescopic rod 4 and the base 2 in three directions of XYZ; the top of the rigid Hooke's hinge 3 is connected to the telescopic rod 4, the telescopic rod 4 is an electric cylinder, the telescopic rod 4 includes a fixed rod 401 installed on the top of the rigid Hooke's hinge 3, and a servo electric cylinder is installed on the outside of the fixed rod 401 The movable cylinder 403 and the top of the fixed rod 401 are connected with the movable rod 402, and the top of the telescopic rod 4 is connected with the top platform 7 through the flexible Hooke's hinge 6. There are six rigid Hooke's hinges 3, telescopic rods 4 and flexible Hooke's hinges 6, two of which are in a group, which are divided into three groups in total. The three groups of rigid Hooke's hinges 3, telescopic rods 4 and flexible Hooke's hinges 6 are distributed in a circular array. The top of the telescopic rod 4 is rotatably connected to the top platform 7 through the flexible Hooke's hinge 6, and the bottom of the telescopic rod 4 is rotatably connected to the base 2 through the rigid Hooke's hinge 3. Six electric cylinder telescopic rods composed of the fixed rod 401, the movable rod 402 and the servo electric cylinder 403 are used to perform independent telescopic movements. The rigid Hooke's hinge 3 and the flexible Hooke's hinge 6 are used to enable the telescopic rod 4 to rotate among the base 2 and the top platform 7, thereby realizing six degrees of freedom of movement of the top platform 7.

[0039] Embodiment 2:

[0040] On the basis of the above-mentioned embodiment 1, in order to facilitate coping with different working situations and working environments, the following settings are now adopted.

[0041] See also Figure 1 In the above embodiment, the telescopic rod 4 is one of a pneumatic cylinder and a hydraulic cylinder. The electric cylinder telescopic rod 4 in the first embodiment can be changed to a pneumatic or hydraulic type, so as to facilitate coping with different working conditions and working environments.

[0042] The implementation principle of the present invention is as follows: first, six electric cylinder telescopic rods composed of a fixed rod 401, a moving rod 402 and a servo electric cylinder 403 are used to perform independent telescopic movements, and the rigid Hooke's hinge 3 and the flexible Hooke's hinge 6 are used to enable the telescopic rod 4 to rotate with the base 2 and the top platform 7, thereby realizing the top platform 7 to move with six degrees of freedom. In addition, the electric cylinder telescopic rod 4 can be changed into a hydraulic or pneumatic telescopic rod 4 according to different working conditions and working environments;

[0043] When a telescopic rod 4 is extended or retracted, it will drive the reading head 502 to move. At this time, the reading head 502 measures and feeds back the macro movement of the top platform 7 corresponding to the magnetic scale 501. However, due to the friction in the structure, the displacement fed back by the reading head 502 in cooperation with the magnetic scale 501 is not the actual displacement of the top platform 7. In addition, since a plurality of through holes are provided on the side of the flexible connection block 601, the flexible connection block 601 is relatively weak, and a more obvious elastic deformation can be produced under the action of torque, thereby converting the friction on the traditional rigid Hooke's hinge 3 and the telescopic rod 4 into the elastic deformation of the flexible Hooke's hinge 6, and detecting the deformation of the flexible connection block 601 through the strain gauge 503, isolating the influence of the friction force of each part, facilitating energy storage and conversion, thereby realizing accurate friction compensation, and combining the displacement feedback of the magnetic scale 501 and the reading head 502, finally realizing the precise positioning of the platform.

[0044] Although an embodiment of the present invention has been shown and described, this specific embodiment is only an explanation of the present invention and is not a limitation of the invention. The specific features, structures, materials or characteristics described may be combined in a suitable manner in any one or more embodiments or examples. After reading this specification, those skilled in the art may make modifications, substitutions and variations to the embodiments without creative contribution as needed without departing from the principles and purpose of the present invention. However, as long as they are within the scope of the claims of the present invention, they are protected by patent law.

Claims

1. A high-precision, low-wear six-degree-of-freedom platform, comprising a test bench (1), a top platform (7), a moving rod (402), a servo electric cylinder (403) and a displacement detector (5), characterized in that: A flexible Hooke's joint (6) is connected between the moving rod (402) and the top platform (7), and the flexible Hooke's joint (6) includes two flexible connection blocks (601), the interiors of the two flexible connection blocks (601) are connected to upper pins (603) via upper bearings (602), and an upper universal joint connection block (604) is connected between the two upper pins (603); the displacement detector (5) includes a strain gauge (503), a reading head (502) is installed on the outer surface of the moving rod (402), and a magnetic scale (501) is connected to one side of the servo electric cylinder (403).

2. The high-precision, low-wear six-degree-of-freedom platform according to claim 1, characterized in that: The flexible connection block (601) is made of POM plastic, spring steel or stainless steel, and a plurality of through holes are provided on one side of the flexible connection block (601).

3. The high-precision, low-wear six-degree-of-freedom platform according to claim 2, characterized in that: The upper universal joint connection block (604) is rotatably connected to the flexible connection block (601) via an upper bearing (602) and an upper pin shaft (603).

4. The high-precision, low-wear six-degree-of-freedom platform according to claim 1, characterized in that: The top of the experimental table (1) is connected to a base (2), and the top of the base (2) is connected to a rigid Hooke's joint (3), the top of the rigid Hooke's joint (3) is connected to a telescopic rod (4), and the top of the telescopic rod (4) is connected to a top platform (7) via a flexible Hooke's joint (6).

5. The high-precision, low-wear six-degree-of-freedom platform according to claim 4, characterized in that: The rigid Hooke's joint (3) comprises a rigid connection block (301) connected to the top of the base (2) and to the bottom of the telescopic rod (4), and the two rigid connection blocks (301) are both connected to lower pins (303) via lower bearings (302), and a lower universal joint connection block (304) is connected between the two lower pins (303).

6. The high-precision, low-wear six-degree-of-freedom platform according to claim 5, characterized in that: The lower universal joint connection block (304) is rotatably connected to the rigid connection block (301) via a lower bearing (302) and a lower pin shaft (303).

7. The high-precision, low-wear six-degree-of-freedom platform according to claim 4, characterized in that: The telescopic rod (4) comprises a fixed rod (401) installed on the top of the rigid Hooke's joint (3), and a servo electric cylinder (403) is installed outside the fixed rod (401), and a moving rod (402) is connected to the top of the fixed rod (401).

8. The high-precision, low-wear six-degree-of-freedom platform according to claim 7, characterized in that: The telescopic rod (4) is one of an electric cylinder, a pneumatic cylinder and a hydraulic cylinder.

9. The high-precision, low-wear six-degree-of-freedom platform according to claim 4, characterized in that: The rigid Hooke's joints (3), telescopic rods (4) and flexible Hooke's joints (6) are each provided in six pieces, two pieces forming a group, and divided into three groups in total. The three groups of rigid Hooke's joints (3), telescopic rods (4) and flexible Hooke's joints (6) are all distributed in a ring array.

10. The high-precision, low-wear six-degree-of-freedom platform according to claim 9, characterized in that: The top end of the telescopic rod (4) is rotatably connected to the top platform (7) via a flexible Hooke's joint (6), and the bottom end of the telescopic rod (4) is rotatably connected to the base (2) via a rigid Hooke's joint (3).

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