High-precision six-degree-of-freedom platform adopting flexible hinges

Abstract

The invention discloses a high-precision six-degree-of-freedom platform adopting flexible hinges, and relates to the technical field of six-degree-of-freedom platforms, the high-precision six-degree-of-freedom platform comprises an experiment table, a fixed rod and a top platform, a magnetic encoder is installed on the fixed rod, a hinge part is arranged in the top platform, and the hinge part comprises two flexible hinges. And a hooke joint fixing seat is connected between the two flexible hinges. Through the arrangement of the magnetic encoder, the strain gauge and the hinge part, the flexible hinge can generate obvious elastic deformation under the action of torque, and can play a role of a hinge in a mechanical structure, so that the flexible hinge is fused into the top platform, and the mechanical structure is more flexible. The friction force between the rigid connecting block and the bearing and the friction force between the bearing and the pin shaft can be converted into elastic deformation in the flexible hinge, so that the influence caused by the friction force of all parts is isolated, energy storage and conversion are facilitated, and the driving and transmission efficiency can be improved; the positioning precision of the system can be effectively improved, and the positioning influence caused by friction is isolated.

Description

Technical Field

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

[0002] Since the legs of the six-degree-of-freedom platform are retractable, 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. Since 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 traditional positioning systems have matured and are widely used, their low accuracy, bulky size, and heavy weight limit their application on carrier platforms. Specifically, during use, traditional positioning systems will reduce the stability of the overall structure due to factors such as load changes and external interference, thereby affecting the positioning accuracy. Since most existing positioning systems adopt a series structure design, cumulative errors are prone to occur during movement, especially in a vibration environment, which will further weaken the structural stability of the system and ultimately affect the positioning accuracy. In addition, future aerospace platforms will gradually tend to be large structures with high flexibility, which will cause their structures to become extremely unstable, and when the system is disturbed, the structural vibration will be more serious, which will also greatly reduce its positioning accuracy. Therefore, the traditional positioning system structure can no longer meet the requirements of the new era for high-precision positioning.

[0004] 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 high-precision flexible Stewart platform was invented, which can effectively improve the positioning accuracy of the system and isolate the positioning effects caused by friction. Summary of the invention

[0005] Based on this, the purpose of the present invention is to provide a high-precision six-degree-of-freedom platform using flexible joints to solve the technical problems mentioned in the above background technology.

[0006] To achieve the above-mentioned purpose, the present invention provides the following technical solutions: a high-precision six-degree-of-freedom platform using flexible joints, comprising a laboratory table, a fixed rod, and a top platform, wherein a magnetic encoder is installed on the fixed rod, a hinged part is arranged inside the top platform, and the hinged part comprises two flexible hinges, a Hooke's hinge fixing seat is connected between the two flexible hinges, and a strain gauge is installed on the top of the flexible hinge.

[0007] By adopting the above technical scheme, the flexible hinge can produce obvious elastic deformation under the action of torque and can play the role of hinge in the mechanical structure. Therefore, the present invention integrates the flexible hinge into the top platform, and can convert the friction between the rigid connecting block and the bearing and between the bearing and the pin shaft into elastic deformation in the flexible hinge, thereby isolating the influence of the friction of each part, facilitating energy storage and conversion, and improving the driving and transmission efficiency. At the same time, according to the displacement data of the electric push rod measured by the magnetic encoder; the flexible hinge displacement data is obtained by strain gauge detection, and the load can be moved to the expected position, thereby achieving precise positioning.

[0008] Furthermore, the flexible hinge is made of POM plastic, spring steel or stainless steel.

[0009] By adopting the above technical solution, the flexible hinge can produce obvious elastic deformation under the action of torque and can play the role of a hinge in the mechanical structure. Therefore, the present invention integrates the flexible hinge into the top platform, which can convert the friction between the rigid connecting block and the bearing and between the bearing and the pin shaft into elastic deformation in the flexible hinge, thereby isolating the influence of the friction of each part, facilitating energy storage and conversion, and improving the driving and transmission efficiency.

[0010] Furthermore, the strain gauges and hinged parts are each provided with six groups, and the six groups of strain gauges are respectively provided at the top of the six groups of hinged parts.

[0011] By adopting the above technical solution, the friction force of the six groups of traditional Hooke's hinges can be converted into elastic deformation in the flexible hinge respectively, thereby isolating the influence of the friction force of each part.

[0012] Furthermore, a base is fixed on the top of the experimental table, and a traditional Hooke's hinge is connected to the top of the base. A telescopic rod is connected to the top of the traditional Hooke's hinge, and the top of the telescopic rod is connected to the Hooke's hinge fixing seat through the traditional Hooke's hinge. A plurality of screw holes are opened on the top of the top platform.

[0013] By adopting the above technical solution, the experimenter fixes the load on the screw hole on the top platform, and then starts the telescopic rod with a magnetic encoder to control the extension and retraction of the telescopic rod. The experimenter can observe that the top platform moves up and down along the Y-axis, and performs independent telescopic movements through six electric cylinder telescopic rods composed of fixed rods and moving rods. The traditional Hooke's hinge enables the telescopic rod to rotate between the base and the top platform, thereby realizing six degrees of freedom movement of the top platform.

[0014] Furthermore, the traditional Hooke's joint includes four rigid connecting blocks connected to the top of the base, connected to the bottom of the telescopic rod, connected to the top of the telescopic rod and connected to the bottom of the Hooke's joint fixing seat, and the four rigid connecting blocks are each connected to a pin shaft through a bearing, and two universal joint connecting blocks are respectively connected between the four pin shafts.

[0015] By adopting the above technical solution, the two rigid connection blocks are connected by a 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.

[0016] Furthermore, the universal joint connection block is rotatably connected to the rigid connection block via a bearing and a pin.

[0017] 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.

[0018] Furthermore, the telescopic rod includes a fixed rod installed on the top of a traditional Hook's hinge, and the top of the fixed rod is connected to a moving rod.

[0019] By adopting the above technical solution, the moving rod extends from the top rod, thereby driving a corner of the top platform to move up or down, so as to achieve six degrees of freedom movement subsequently.

[0020] Furthermore, six of the conventional Hooke's hinges and telescopic rods are provided, two in a group, and divided into three groups in total, and the three groups of conventional Hooke's hinges and telescopic rods are distributed in a ring array.

[0021] By adopting the above technical solution, six electric cylinder telescopic rods composed of fixed rods and moving rods can perform independent telescopic movements, thereby adjusting the heights of the three corners of the top platform and realizing six degrees of freedom movement of the top platform.

[0022] Furthermore, both ends of the telescopic rod are rotatably connected to the base and the Hooke's hinge fixing seat respectively through traditional Hooke's hinges.

[0023] By adopting the above technical solution, the traditional Hooke's joint enables the telescopic rod to rotate with the base and the top platform, thereby realizing six degrees of freedom movement of the top platform.

[0024] Furthermore, the telescopic rod is one of an electric cylinder, a pneumatic cylinder and a hydraulic cylinder.

[0025] By adopting the above technical solution, the electric cylinder type telescopic rod can be changed into a hydraulic or pneumatic telescopic rod according to different working conditions and working environments, thereby reducing limitations during use.

[0026] In summary, the present invention mainly has the following beneficial effects:

[0027] The present invention arranges a magnetic encoder, a strain gauge and a hinge part, so that the flexible hinge can produce obvious elastic deformation under the action of torque and can play the role of a hinge in a mechanical structure. Therefore, the present invention integrates the flexible hinge into the top platform, and can convert the friction between the rigid connecting block and the bearing and between the bearing and the pin shaft into elastic deformation in the flexible hinge, thereby isolating the influence of the friction of each part, facilitating energy storage and conversion, and improving the driving and transmission efficiency. At the same time, according to the displacement data of the electric push rod measured by the magnetic encoder; and then the flexible hinge displacement data is obtained by strain gauge detection, the load can be moved to the expected position, thereby achieving precise positioning; the positioning accuracy of the system can be effectively improved and the positioning influence caused by the isolation friction can be effectively improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a structural schematic diagram of the present invention;

[0029] Figure 2 It is a schematic diagram of the top view of the structure of the present invention;

[0030] Figure 3 It is a schematic diagram of the top platform structure of the present invention;

[0031] Figure 4 It is a schematic diagram of the traditional Hooke's hinge structure of the present invention;

[0032] Figure 5 It is a schematic diagram of the telescopic rod structure of the present invention.

[0033] In the figure: 1. Experimental table; 2. Base; 3. Traditional Hooke's hinge; 301. Rigid connecting block; 302. Bearing; 303. Pin; 304. Universal joint connecting block; 4. Telescopic rod; 401. Fixed rod; 402. Moving rod; 403. Magnetic encoder; 5. Strain gauge; 6. Articulated part; 601. Hooke's hinge fixing seat; 602. Flexible hinge; 7. Top platform; 8. Screw hole. 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 six-degree-of-freedom platform using flexible joints, such as Figure 1 , Figure 2 , Figure 3 and Figure 5 As shown, it includes a test bench 1, a fixed rod 401, and a top platform 7. A magnetic encoder 403 is installed on the fixed rod 401. A hinged portion 6 is arranged inside the top platform 7. The hinged portion 6 includes two flexible hinges 602. The flexible hinges 602 are made of POM plastic, spring steel or stainless steel. A Hooke's hinge fixing seat 601 is connected between the two flexible hinges 602. A strain gauge 5 is installed on the top of the flexible hinge 602. Six groups of strain gauges 5 and the hinged portion 6 are arranged. The six groups of strain gauges 5 are respectively arranged on the top of the six groups of hinged portions 6. The flexible hinge 602 is connected to the top of the flexible hinge 602 under the force. Under the action of torque, it can produce obvious elastic deformation and play the role of hinge in the mechanical structure. By integrating the flexible hinge 602 into the top platform 7, the friction between the rigid connection block 301 and the bearing 302 and between the bearing 302 and the pin 303 can be converted into elastic deformation in the flexible hinge 602, thereby isolating the influence of the friction of each part, facilitating energy storage and conversion, and improving the driving and transmission efficiency. The displacement data of the flexible hinge 602 can be obtained by detecting the strain gauge 5, and the load can be moved to the expected position, thereby achieving precise positioning.

[0038] See also Figure 1-Figure 5 In the above embodiment, a base 2 is fixed on the top of the experimental table 1, a traditional Hooke's hinge 3 is connected to the top of the base 2, a telescopic rod 4 is connected to the top of the traditional Hooke's hinge 3, the telescopic rod 4 includes a fixed rod 401 installed on the top of the traditional Hooke's hinge 3, a moving rod 402 is connected to the top of the fixed rod 401, the top of the telescopic rod 4 is connected to the Hooke's hinge fixing seat 601 through the traditional Hooke's hinge 3, the traditional Hooke's hinge 3 includes four rigid connection blocks 301 connected to the top of the base 2, connected to the bottom of the telescopic rod 4, connected to the top of the telescopic rod 4 and connected to the bottom of the Hooke's hinge fixing seat 601, the four rigid connection blocks 301 are all connected to the pin shaft 303 through the bearing 302, the four pin shafts 303 are respectively connected to two universal joint connection blocks 304, the universal joint connection block 304 is connected to the rigid connection block 3 through the bearing 302 and the pin shaft 303 01 rotational connection, six traditional Hooke's hinges 3 and telescopic rods 4 are provided, two in a group, and a total of three groups. The three groups of traditional Hooke's hinges 3 and telescopic rods 4 are distributed in a circular array. The two ends of the telescopic rod 4 are rotationally connected to the base 2 and the Hooke's hinge fixing seat 601 through the traditional Hooke's hinge 3 respectively. A plurality of screw holes 8 are opened on the top of the top platform 7. The experimenter fixes the load in the screw holes 8 on the top platform 7, and then the experimenter starts the telescopic rod 4 with the magnetic encoder 403 to control the extension and retraction of the telescopic rod 4. The experimenter can observe that the top platform 7 moves up and down along the Y-axis, and the six electric cylinder telescopic rods 4 composed of fixed rods 401 and moving rods 402 perform independent telescopic movements, and cooperate with the traditional Hooke's hinge 3 to enable the telescopic rod 4 to rotate with the base 2 and the top platform 7, thereby realizing the six-degree-of-freedom 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 adopted.

[0041] See also Figure 1 and Figure 2 In the above embodiment, the telescopic rod 4 is one of an electric cylinder, a gas cylinder and a hydraulic cylinder. According to different working conditions and working environments, the electric cylinder type telescopic rod 4 can be changed to a hydraulic or pneumatic telescopic rod 4.

[0042] The implementation principle of the present invention is as follows: first, the experimenter fixes the load to the screw hole 8 on the top platform 7, and then the experimenter starts the telescopic rod 4 with the magnetic encoder 403 to control the extension and retraction of the telescopic rod 4. The experimenter can observe that the top platform 7 moves up and down along the Y axis, and obtains the displacement data of the telescopic rod 4 according to the measurement of the magnetic encoder 403;

[0043] Six electric cylinder telescopic rods 4 composed of fixed rods 401 and moving rods 402 are used to perform independent telescopic movement, and the telescopic rods 4, the base 2 and the top platform 7 can be rotated with the traditional Hook hinge 3, so that the top platform 7 can move with six degrees of freedom. According to different working conditions and working environments, the electric cylinder telescopic rods 4 can be changed into hydraulic or pneumatic telescopic rods 4;

[0044] At the same time, the flexible hinge 602 can produce obvious elastic deformation under the action of torque, and can play the role of a hinge in the mechanical structure. By integrating the flexible hinge 602 into the top platform 7, the friction between the rigid connecting block 301 and the bearing 302 and between the bearing 302 and the pin 303 can be converted into elastic deformation in the flexible hinge 602, thereby isolating the influence of the friction of each part, facilitating energy storage and conversion, and improving the driving and transmission efficiency. The displacement data of the flexible hinge 602 is then obtained through the strain gauge 5, and the load can be moved to the expected position, thereby achieving precise positioning.

[0045] 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 six-degree-of-freedom platform using a flexible joint, comprising a test bench (1), a fixed rod (401), and a top platform (7), characterized in that: A magnetic encoder (403) is installed on the fixed rod (401), a hinge part (6) is arranged inside the top platform (7), and the hinge part (6) includes two flexible hinges (602), a Hooke's hinge fixing seat (601) is connected between the two flexible hinges (602), and a strain gauge (5) is installed on the top of the flexible hinge (602).

2. The high-precision six-degree-of-freedom platform using flexible joints according to claim 1, characterized in that: The flexible hinge (602) is made of POM plastic, spring steel or stainless steel.

3. The high-precision six-degree-of-freedom platform using flexible joints according to claim 1, characterized in that: The strain gauges (5) and hinged parts (6) are each provided with six groups, and the six groups of strain gauges (5) are respectively provided at the tops of the six groups of hinged parts (6).

4. The high-precision six-degree-of-freedom platform using flexible joints according to claim 1, characterized in that: A base (2) is fixed on the top of the experimental table (1), and a traditional Hooke's hinge (3) is connected to the top of the base (2), a telescopic rod (4) is connected to the top of the traditional Hooke's hinge (3), and the top of the telescopic rod (4) is connected to the Hooke's hinge fixing seat (601) through the traditional Hooke's hinge (3), and a plurality of screw holes (8) are opened on the top of the top platform (7).

5. The high-precision six-degree-of-freedom platform using flexible joints according to claim 4, characterized in that: The conventional Hooke's joint (3) comprises four rigid connection blocks (301) connected to the top of the base (2), connected to the bottom of the telescopic rod (4), connected to the top of the telescopic rod (4) and connected to the bottom of the Hooke's joint fixing seat (601), and the four rigid connection blocks (301) are all connected to pins (303) via bearings (302), and two universal joint connection blocks (304) are respectively connected between the four pins (303).

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

7. The high-precision six-degree-of-freedom platform using flexible joints according to claim 4, characterized in that: The telescopic rod (4) comprises a fixed rod (401) installed on the top of a conventional Hooke's hinge (3), and a movable rod (402) is connected to the top of the fixed rod (401).

8. The high-precision six-degree-of-freedom platform using flexible joints according to claim 7, characterized in that: Six of the conventional Hooke's hinges (3) and telescopic rods (4) are provided, two in a group, and a total of three groups, and the three groups of conventional Hooke's hinges (3) and telescopic rods (4) are distributed in a ring array.

9. The high-precision six-degree-of-freedom platform using flexible joints according to claim 8, characterized in that: The two ends of the telescopic rod (4) are rotatably connected to the base (2) and the Hooke's hinge fixing seat (601) respectively through a conventional Hooke's hinge (3).

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

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