Flexible hinge decoupled six-degree-of-freedom parallel motion platform and control method

Abstract

This invention discloses a six-degree-of-freedom parallel motion platform and control method with flexible hinge decoupling, belonging to the field of precision drive and control technology. The invention includes a moving platform, a stationary platform, and six moving legs. The moving platform and the stationary platform are coaxially parallel and triangularly orthogonal. Each of the six legs is composed of a first flexible hinge, a second flexible hinge, and a linear drive assembly. The first and second flexible hinges achieve flexible decoupling by reducing the bending stiffness of the legs through material elastic deformation, and connect the moving platform and the stationary platform by bolts. The linear drive assembly changes the motion form of the actuator to achieve macro-motion and micro-motion. In this invention, both the flexible hinges and the drive assembly adopt a modular design, enabling large-stroke, high-precision motion along the X, Y, and Z axes. The six-degree-of-freedom parallel structure design improves the overall load capacity of the platform under the limited load of a single drive unit and enables rotation around the X, Y, and Z axes.

Description

Technical Field

[0001] This invention relates to a six-degree-of-freedom parallel motion platform and control method with flexible hinge decoupling, belonging to the field of precision drive and control technology. Background Technology

[0002] In recent years, with the development of precision mechanical technology, especially the emergence of micro- and nanotechnology, science and technology have officially entered the "submicron-nanometer" era. Traditional macroscopic operations can no longer meet the demands of production. Scanning electron microscopes, optical instruments, precision machining, and other fields in electronics, optics, mechanics, and aerospace urgently require high-precision, high-resolution, and high-speed positioning platforms; moreover, the demand for multi-degree-of-freedom precision positioning platforms is even more urgent. For example, the ultra-high resolution and high-precision rotation of astronomical telescopes require multi-degree-of-freedom positioning platforms; the processing and assembly of precision optical instruments require multi-degree-of-freedom precision positioning platforms; medical surgery increasingly relies on multi-degree-of-freedom precision end-effectors, and so on.

[0003] Current precision motion platforms mostly employ traditional mechanical transmission mechanisms, such as screw mechanisms, lever mechanisms, wedge block cam mechanisms, and combinations thereof. The biggest advantage of mechanical transmission mechanisms is their simple structure and large stroke; however, their structure is highly susceptible to cumulative motion errors and exhibits low structural stability when exposed to vibration, making precise pointing control difficult. Therefore, traditional mechanical transmission mechanisms can no longer meet the precision motion technology requirements of these platforms.

[0004] With the deepening research on parallel structures and the continuous development of control technology, a new type of motion platform based on intelligent structures has brought a new research direction to the solution of this type of problem. This type of platform is based on the Stewart six-DOF parallel platform, and can achieve six degrees of freedom motion through the coordinated movement of six drive rods. Currently, most Stewart six-DOF parallel platforms are rigid structures, large in size, and suffer from problems such as strong parallel coupling and poor control stability, making them unsuitable for precision positioning systems. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the prior art and provide a six-degree-of-freedom parallel motion platform and control method with flexible hinge decoupling, which reduces the output stiffness of the outriggers to achieve flexible decoupling, and realizes six-degree-of-freedom motion through different drive combinations.

[0006] To achieve the above objectives, the present invention is implemented using the following technical solution:

[0007] In a first aspect, the present invention provides a six-degree-of-freedom parallel motion platform with flexible hinge decoupling, comprising: a moving platform, a stationary platform, and six moving legs, wherein the moving legs include a first flexible hinge, a second flexible hinge, and a linear drive assembly;

[0008] The moving platform and the stationary platform are placed coaxially and parallel to each other in a compact manner. The moving platform and the stationary platform are respectively connected to six legs, and the two platforms are connected in a triangular orthogonal structure. The first flexible hinge connects the moving platform, and the second flexible hinge connects the stationary platform. The linear drive assembly connects the first flexible hinge and the second flexible hinge. The linear drive assembly is used to drive the flexible hinge to move, so as to realize the translation of the moving platform along the three directions of X, Y, and Z and the rotation around the three axes of X, Y, and Z.

[0009] Furthermore, the linear drive assembly includes a driver housing, a driver end cover, a guide rail, an output shaft, an actuating shaft, a rhombic amplification mechanism, a first clamping semi-rhombic amplification mechanism, a second clamping semi-rhombic amplification mechanism, a drive piezoelectric stack, a first clamping piezoelectric stack, and a second clamping piezoelectric stack. The position of the linear drive assembly is fixed by the driver housing and the driver end cover. The guide rail is disposed inside the driver housing. The output shaft and the actuating shaft both move on the guide rail and are connected through the rhombic amplification mechanism. The first clamping semi-rhombic amplification mechanism is located inside the driver housing and clamps the actuating shaft. The second clamping semi-rhombic amplification mechanism is located inside the driver housing and clamps the output shaft. The drive piezoelectric stack is located in the rhombic amplification mechanism. The first clamping piezoelectric stack is located in the first clamping semi-rhombic amplification mechanism, and the second clamping piezoelectric stack is located in the second clamping semi-rhombic amplification mechanism.

[0010] Furthermore, the driver end cover, guide rail, first half-diamond amplification mechanism, and second half-diamond amplification mechanism are all fixed to the driver housing by set screws.

[0011] Furthermore, the drive component is connected to a motion control module, which divides the motion of the moving platform into translational motion control signals and rotational motion control signals. The control signals are then solved using inverse kinematics to control the motion of the moving platform by the drive component. The motion control module includes sensors that detect the position and attitude of the platform and use them as displacement feedback signals for the controller to achieve closed-loop control.

[0012] Furthermore, the linear drive component changes the motion form of the actuator to achieve macro-motion and micro-motion, and drives the motion support leg to achieve multi-degree-of-freedom motion of the moving platform.

[0013] Furthermore, the linear drive component is any one of a piezoelectric inchworm actuator, a piezoelectric stack actuator, or a rhombic amplifier actuator.

[0014] Furthermore, the first flexible hinge and the second flexible hinge are any one of Y-type, X-type, and V-type flexible hinges.

[0015] Furthermore, the first flexible hinge and the second flexible hinge are connected to the moving platform and the stationary platform by bolts; the linear drive assembly is connected to the first flexible hinge and the second flexible hinge by adhesive or bolts.

[0016] Secondly, the present invention provides a control method for a six-degree-of-freedom parallel motion platform decoupled by flexible hinges according to any one of the foregoing claims, comprising:

[0017] In the first clamping semi-rhomboid amplification mechanism, the first clamping piezoelectric stack is energized and elongated, releasing the clamping state;

[0018] When the driving piezoelectric stack in the rhombic amplification mechanism is energized, it elongates, and the distance between its two output ends shortens, causing the right-end actuating shaft to move to the left.

[0019] The first clamping piezoelectric stack in the first clamping semi-rhomboid amplification mechanism is de-energized, restoring the clamping state and clamping the right-end actuating shaft;

[0020] The second clamping piezoelectric stack in the second clamping semi-rhomboid amplification mechanism is energized and elongated, releasing the clamping state;

[0021] When the driving piezoelectric stack in the rhombic amplification mechanism is de-energized and shortened, the distance between its two output ends returns to its initial state, pushing the left output shaft to move to the left.

[0022] The second clamping piezoelectric stack in the second clamping semi-rhomboid amplification mechanism is de-energized, restoring the clamping state and clamping the left output shaft;

[0023] By repeating the above steps, the linear drive component achieves large stroke displacement output through continuous feeding.

[0024] Furthermore, the control method also includes:

[0025] The first clamping semi-rhomboid amplification mechanism is always in the clamped state, and the second clamping semi-rhomboid amplification mechanism is always in the unclamped state.

[0026] By controlling whether the drive piezoelectric stack in the rhombic amplification mechanism is energized, the micro-motion positioning function of the multi-degree-of-freedom parallel motion platform can be realized.

[0027] Compared with the prior art, the beneficial effects achieved by the present invention are as follows:

[0028] This invention provides a six-degree-of-freedom parallel motion platform and control method with flexible hinge decoupling. Its features include flexible hinges that reduce the output stiffness of the outriggers to achieve flexible decoupling, and different drive combinations to achieve six-degree-of-freedom motion. On the one hand, mechanical decoupling achieves high motion accuracy and can realize both macro and micro motion modes. On the other hand, due to the structural characteristics of the triangular orthogonal platform, the entire motion platform has a compact structure and can withstand large loads. Attached Figure Description

[0029] Figure 1 This is a three-dimensional view of the platform of the present invention;

[0030] Figure 2 This is a front view of the platform of the present invention;

[0031] Figure 3 This is a top view of the platform of the present invention;

[0032] Figure 4 This invention relates to a piezoelectric stack drive platform with the same structure.

[0033] Figure 5 The present invention relates to a rhombic amplification drive platform with the same structure;

[0034] Figure 6 The preferred embodiment of the flexible hinge of the present invention is a Y-type hinge;

[0035] Figure 7 This is another embodiment of the flexible hinge of the present invention: the X-type hinge;

[0036] Figure 8 This is another embodiment of the flexible hinge of the present invention: the V-shaped hinge;

[0037] Figure 9 The preferred embodiment of the linear actuator of the present invention is a piezoelectric inchworm actuator;

[0038] Figure 10 This is a preferred embodiment of the linear actuator of the present invention: a piezoelectric stacked actuator.

[0039] Figure 11 The preferred embodiment of the linear driver of the present invention is a rhombus amplification driver;

[0040] In the figure: 1. Moving platform; 2. Static platform; 3. First flexible hinge; 4. Second flexible hinge; 5. Linear drive assembly; 5-1. Driver housing; 5-2. Driver end cover; 5-3. Guide rail; 5-4. Output shaft; 5-5. Actuating shaft; 5-6. Rhomboid amplification mechanism; 5-7. First clamped semi-rhomboid amplification mechanism; 5-8. Second clamped semi-rhomboid amplification mechanism; 5-9-1. Drive piezoelectric stack; 5-9-2. First clamped piezoelectric stack; 5-9-3. Second clamped piezoelectric stack. Detailed Implementation

[0041] The present invention will be further described below with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and should not be used to limit the scope of protection of the present invention.

[0042] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0043] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art will understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0044] Example 1

[0045] like Figure 1 As shown in the figure, this embodiment introduces a six-degree-of-freedom parallel motion platform with flexible hinge decoupling, including: a moving platform 1, a stationary platform 2, and six moving legs. The moving legs include a first flexible hinge 3, a second flexible hinge 4, and a linear drive assembly 5.

[0046] like Figure 3 and Figure 4 As shown, the moving platform 1 and the stationary platform 2 are placed coaxially and parallel, and are connected to six legs respectively. The two platforms are connected in a triangular orthogonal structure. The first flexible hinge 3 and the second flexible hinge 4 are connected to the moving platform 1 and the stationary platform 2 by bolts. The linear drive assembly 5 is connected to the first flexible hinge 3 and the second flexible hinge 4 by adhesive or bolts.

[0047] like Figure 4 and Figure 5 As shown, the motion support leg can be configured with different linear drive components 5 to form other platforms with the same structure to achieve multi-degree-of-freedom precision motion.

[0048] like Figure 4 , Figure 5 and Figure 6 As shown, the first flexible hinge 3 and the second flexible hinge 4 achieve flexible decoupling by reducing the bending stiffness of the outriggers through the elastic deformation of the materials.

[0049] Furthermore, the first flexible hinge 3 and the second flexible hinge 4 are preferably Y-shaped, but can also be known new flexible hinges such as X-shaped or V-shaped. The direction of the flexible hinge is to ensure that the stiffness in the orthogonal direction is minimized.

[0050] like Figure 7 , Figure 8 and Figure 9 As shown, the linear drive component 5 changes the motion form of the actuator to achieve macro-motion and micro-motion, and drives the outrigger to achieve multi-degree-of-freedom motion of the moving platform 1.

[0051] Furthermore, the linear drive component 5 is preferably a piezoelectric inchworm actuator, but it can also be a known piezoelectric stack actuator, rhombic amplifier actuator, or other components that can achieve linear drive.

[0052] like Figure 1 As shown, the driving component 5 pushes the flexible hinge 3 to move, thereby realizing the translation of the moving platform 1 along the three directions of X, Y, and Z and the rotation around the three axes of X, Y, and Z.

[0053] Furthermore, the drive assembly 5 is connected to a motion control module. This module divides the motion of the moving platform 1 into translational motion control signals and rotational motion control signals. It then performs inverse kinematics calculations on these control signals to direct the drive assembly 5 to control the motion of the moving platform 1. The motion control module includes sensors that detect the platform's position and attitude, providing displacement feedback signals to the controller for closed-loop control.

[0054] As a preferred embodiment of the present invention, the specific details are as follows:

[0055] like Figure 9As shown, the linear drive assembly 5 includes a driver housing 5-1, a driver end cover 5-2, a guide rail 5-3, an output shaft 5-4, an actuation shaft 5-5, a rhombic amplification mechanism 5-6, a first clamping semi-rhombic amplification mechanism 5-7, a second clamping semi-rhombic amplification mechanism 5-8, and driving piezoelectric stacks 5-9-1, 5-9-2, and 5-9-3. The position of the piezoelectric inchworm driver 5 is fixed by the driver housing 5-1 and the driver end cover 5-2. The output shaft 5-4 and the actuation shaft 5-5 both move on the guide rail 5-3 and are connected by the rhombic amplification mechanism 5-6. The piezoelectric stacks 5-9 are located in the rhombic amplification mechanism 5-6, the first clamping semi-rhombic amplification mechanism 5-7, and the second clamping semi-rhombic amplification mechanism 5-8, respectively, and deform through the reverse electrostatic effect. The actuator housing 5-1 is fitted over the actuator. The actuator end cover 5-2, guide rail 5-3, first half-diamond amplification mechanism 5-7 and second half-diamond amplification mechanism 5-8 are all connected and fixed by set screws.

[0056] In this implementation example, the actuator's movement is as follows: First, the first clamping piezoelectric stack 5-9-2 in the first clamping semi-rhomboid amplification mechanism 5-7 is energized and extends, releasing the clamping state; Second, the driving piezoelectric stack 5-9-1 in the rhomboid amplification mechanism 5-6 is energized and extends, shortening the distance between its two output ends, causing the right-end actuating shaft 5-5 to move to the left; Third, the first clamping piezoelectric stack 5-9-2 in the first clamping semi-rhomboid amplification mechanism 5-7 is de-energized, restoring the clamping state and clamping the right-end actuating shaft 5-5; Fourth, the first... The second clamping piezoelectric stack 5-9-3 is energized and elongates, releasing the clamping state; in the fifth step, the driving piezoelectric stack 5-9-1 in the rhombic amplification mechanism 5-6 is de-energized and shortens, restoring the distance between its two output ends to the initial state, pushing the left output shaft 5-4 to the left; in the sixth step, the second clamping piezoelectric stack 5-9-3 in the second clamping semi-rhombic amplification mechanism 5-8 is de-energized, restoring the clamping state and clamping the left output shaft 5-4; by repeating the above steps, the linear drive assembly 5 achieves large stroke displacement output through continuous feeding, and the multi-degree-of-freedom parallel motion platform can achieve a wide range of precision tracking functions.

[0057] Example 2

[0058] The difference between this embodiment and Implementation Case 1 lies in the motion form of the actuator, as follows: the first clamping semi-rhomboid amplification mechanism 5-7 is always in the clamping state, and the second clamping semi-rhomboid amplification mechanism 5-8 is always in the unclamped state. At this time, the actuator is in the scanning state, also known as the linear state. Whether the extension drive piezoelectric stack 5-9-1 is energized is determined by the external controller. At this time, the actuator displacement is small, the response is fast, and the accuracy is high, which can realize the micro-motion positioning function of the multi-degree-of-freedom parallel motion platform.

[0059] Example 3

[0060] This embodiment provides a control method for a six-degree-of-freedom parallel motion platform with flexible hinge decoupling according to any one of Embodiment 1, including:

[0061] The first clamping piezoelectric stack 5-9-2 in the first clamping semi-rhomboid amplification mechanism 5-7 is energized and elongated to release the clamping state;

[0062] When the driving piezoelectric stack 5-9-1 in the rhombic amplification mechanism 5-6 is energized, it extends and the distance between its two output ends shortens, causing the right-end actuating shaft 5-5 to move to the left.

[0063] The first clamping piezoelectric stack 5-9-2 in the first clamping semi-rhomboid amplification mechanism 5-7 is de-energized, restoring the clamping state and clamping the right end actuating shaft 5-5;

[0064] The second clamping piezoelectric stack 5-9-3 in the second clamping semi-rhomboid amplification mechanism 5-8 is energized and elongated to release the clamping state;

[0065] When the driving piezoelectric stack 5-9-1 in the rhombic amplification mechanism 5-6 is de-energized and shortened, the distance between its two output ends returns to the initial state, pushing the left output shaft 5-4 to the left.

[0066] The second clamping piezoelectric stack 5-9-3 in the second clamping semi-rhomboid amplification mechanism 5-8 is de-energized, restoring the clamping state and clamping the left output shaft 5-4;

[0067] By repeating the above steps, the linear drive component 5 achieves large stroke displacement output through continuous feeding.

[0068] The control method further includes:

[0069] The first clamping semi-rhomboid amplification mechanism 5-7 is always in the clamped state, and the second clamping semi-rhomboid amplification mechanism 5-8 is always in the unclamped state.

[0070] By controlling whether the drive piezoelectric stack 5-9-1 in the rhombic amplification mechanism 5-6 is energized, the micro-motion positioning function of the multi-degree-of-freedom parallel motion platform 1 can be realized.

[0071] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A flexible-hinge decoupled six-degree-of-freedom parallel kinematic platform, characterized by, include: The platform consists of a moving platform (1), a static platform (2), and six moving legs, each of which includes a first flexible hinge (3), a second flexible hinge (4), and a linear drive assembly (5). The moving platform (1) and the stationary platform (2) are placed coaxially and parallel to each other in a compact manner. The moving platform (1) and the stationary platform (2) are respectively connected to six legs, and the two platforms are connected in a triangular orthogonal structure. The first flexible hinge (3) connects the moving platform (1), and the second flexible hinge (4) connects the stationary platform (2). The linear drive assembly (5) connects the first flexible hinge (3) and the second flexible hinge (4). The linear drive assembly (5) is used to drive the flexible hinge to move, so that the moving platform (1) can translate along the three directions of X, Y, and Z and rotate around the three axes of X, Y, and Z. The linear drive assembly (5) includes a driver housing (5-1), a driver end cover (5-2), a guide rail (5-3), an output shaft (5-4), an actuation shaft (5-5), a rhombic amplification mechanism (5-6), a first clamping semi-rhombic amplification mechanism (5-7), a second clamping semi-rhombic amplification mechanism (5-8), a drive piezoelectric stack (5-9-1), a first clamping piezoelectric stack (5-9-2), and a second clamping piezoelectric stack (5-9-3). The position of the linear drive assembly (5) is fixed by the driver housing (5-1) and the driver end cover (5-2). The guide rail (5-3) is disposed inside the driver housing (5-1). The output shaft (5-4) and... The actuating shafts (5-5) all move on the guide rails (5-3) and are connected by the rhomboid amplification mechanism (5-6); the first clamping semi-rhomboid amplification mechanism (5-7) is located inside the driver housing (5-1) and clamps the actuating shaft (5-5); the second clamping semi-rhomboid amplification mechanism (5-8) is located inside the driver housing (5-1) and clamps the output shaft (5-4); the driving piezoelectric stack (5-9-1) is located in the rhomboid amplification mechanism (5-6); the first clamping piezoelectric stack (5-9-2) is located in the first clamping semi-rhomboid amplification mechanism (5-7); and the second clamping piezoelectric stack (5-9-3) is located in the second clamping semi-rhomboid amplification mechanism (5-8).

2. The six-degree-of-freedom parallel motion platform with flexible hinge decoupling according to claim 1, characterized in that, The driver end cover (5-2), guide rail (5-3), first clamping semi-rhomboid amplification mechanism (5-7), and second clamping semi-rhomboid amplification mechanism (5-8) are all fixed to the driver housing (5-1) by set screws.

3. The six-degree-of-freedom parallel motion platform with flexible hinge decoupling according to claim 1, characterized in that, The linear drive assembly is connected to a motion control module. The motion control module divides the motion of the moving platform (1) into translational motion control signals and rotational motion control signals. The control signals are solved by inverse kinematics to realize the linear drive assembly controlling the motion of the moving platform (1). The motion control module includes a sensor. The sensor is used to detect the position and attitude of the platform and serves as the displacement feedback signal of the controller to realize closed-loop control.

4. The six-degree-of-freedom parallel motion platform with flexible hinge decoupling according to claim 1, characterized in that, The linear drive component (5) changes the motion form of the actuator to realize macro motion and micro motion, and drives the motion support leg to realize the multi-degree-of-freedom motion of the moving platform (1).

5. The six-degree-of-freedom parallel motion platform with flexible hinge decoupling according to claim 1, characterized in that, The first flexible hinge (3) and the second flexible hinge (4) are any one of Y-type, X-type and V-type flexible hinges.

6. The six-degree-of-freedom parallel motion platform with flexible hinge decoupling according to claim 1, characterized in that, The first flexible hinge (3) and the second flexible hinge (4) are connected to the moving platform (1) and the stationary platform (2) by bolts; the linear drive assembly (5) is connected to the first flexible hinge (3) and the second flexible hinge (4) by adhesive or bolts.

7. A control method for a six-degree-of-freedom parallel motion platform with flexible hinge decoupling according to claim 1, characterized in that, include: The first clamping piezoelectric stack (5-9-2) in the first clamping semi-rhomboid amplification mechanism (5-7) is energized and elongated to release the clamping state; When the driving piezoelectric stack (5-9-1) in the rhombic amplification mechanism (5-6) is energized, it elongates and the distance between its two output ends shortens, causing the right-end actuating shaft (5-5) to move to the left. The first clamping piezoelectric stack (5-9-2) in the first clamping semi-rhomboid amplification mechanism (5-7) is de-energized, restoring the clamping state and clamping the right end actuating shaft (5-5); The second clamping piezoelectric stack (5-9-3) in the second clamping semi-rhomboid amplification mechanism (5-8) is energized and elongated to release the clamping state; When the driving piezoelectric stack (5-9-1) in the rhombic amplification mechanism (5-6) is de-energized and shortened, the distance between its two output ends returns to the initial state, pushing the left output shaft (5-4) to the left. The second clamping piezoelectric stack (5-9-3) in the second clamping semi-rhomboid amplification mechanism (5-8) is de-energized, restoring the clamping state and clamping the left output shaft (5-4); By repeating the above steps, the linear drive component (5) achieves large stroke displacement output through continuous feeding.

8. The control method for a six-degree-of-freedom parallel motion platform with flexible hinge decoupling according to claim 7, characterized in that, include: The first clamping semi-rhomboid amplification mechanism (5-7) is always in the clamped state, and the second clamping semi-rhomboid amplification mechanism (5-8) is always in the unclamped state. By controlling whether the driving piezoelectric stack (5-9-1) in the rhombic amplification mechanism (5-6) is energized, the micro-motion positioning function of the multi-degree-of-freedom parallel motion platform can be realized.

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