Two-degree-of-freedom angular displacement piezoelectric actuation platform

Abstract

The application discloses a two-degree-of-freedom angular displacement piezoelectric actuating platform, which comprises an angular displacement positioning platform, an x-axis angular displacement main component, a y-axis angular displacement main component, a pre-tightening bolt, a positioning top block, a first piezoelectric ceramic stack, a second piezoelectric ceramic stack, a first rotating pad and a second rotating pad, the x-axis angular displacement main component and the y-axis angular displacement main component are cross-connected in a cross shape along the x-axis and the y-axis, the angular displacement positioning platform is arranged above the x-axis angular displacement main component and the y-axis angular displacement main component, the bottom end of the pre-tightening bolt is abutted against the positioning top block, the first piezoelectric ceramic stack is horizontally arranged between the positioning top block and the first rotating pad, the first rotating pad is connected with a supporting block on the x-axis, the second piezoelectric ceramic stack is horizontally arranged between the positioning top block and the second rotating pad, and the second rotating pad is connected with a supporting block on the y-axis.The two-degree-of-freedom (θ x ‑θ y ) angular displacement positioning is realized by using two piezoelectric ceramic stacks for driving.

Description

Technical Field

[0001] This invention relates to the field of micro-positioning rotation platforms, and in particular to a two-degree-of-freedom angular displacement piezoelectric actuation platform. Background Technology

[0002] As the demands on nanotechnology increase in fields such as optical communication, aerial remote sensing, semiconductors, and biomedicine, rotating platforms with micro-nano deflection mechanisms are becoming increasingly important in modern positioning technologies. In aerial remote sensing, the purpose of this deflection mechanism is to rotate a reflector at high speed and high precision to deflect the light beam, suppressing the impact of aerial camera vibration on image quality. Most deflection positioning mechanisms are driven by voice coil motors because voice coil motors can typically provide a large rotation range, but these electromagnetic mechanisms have disadvantages such as low resonant frequency, high power consumption, and susceptibility to magnetic field interference. In contrast, positioning platforms designed with piezoelectric ceramic stacks have advantages in terms of high resolution, cost-effectiveness, and absence of electromagnetic interference. However, research on high-performance two-degree-of-freedom angular displacement piezoelectric actuation platforms is limited. The existing Chinese invention patent (CN103177774B) uses four piezoelectric stacks to achieve two-degree-of-freedom platform rotation, but the stack utilization rate is low and the structure is not compact enough.

[0003] Due to the very small deformation range of piezoelectric materials, the angular travel of existing piezoelectric deflection platforms is typically very small. A common method to increase this deflection range is to use larger piezoelectric stacks. However, larger piezoelectric stacks result in greater energy consumption, and the excessively large size of the tilting platform limits its application in many fields. In the development of micro-positioning rotary platforms from one-dimensional to multi-dimensional, motion coupling is the key factor affecting rotational accuracy and performance. Effective decoupling and suppressing its coupling effects within the structure are essential requirements for achieving high-performance multi-dimensional applications. Summary of the Invention

[0004] The purpose of this invention is to provide a two-degree-of-freedom angular displacement piezoelectric actuation platform, which uses two piezoelectric ceramic stacks to drive two degrees of freedom (θ). x -θ y The angular displacement positioning platform reduces the number of piezoelectric ceramic stacks, saving costs, reducing energy consumption, and improving its applicability in various fields.

[0005] To achieve the above objectives, the technical solution adopted by this invention is as follows:

[0006] A two-degree-of-freedom angular displacement piezoelectric actuation platform includes an angular displacement positioning platform, an x-axis angular displacement main component, a y-axis angular displacement main component, preload bolts, a positioning top block, a first piezoelectric ceramic stack, a second piezoelectric ceramic stack, a first rotating pad, and a second rotating pad. The x-axis and y-axis angular displacement main components are cross-connected along the x and y axes. The angular displacement positioning platform is positioned above the x-axis and y-axis angular displacement main components. The preload bolt is screwed into the x-axis and y-axis angular displacement main components, with its bottom end resting on the positioning top block. The first piezoelectric ceramic stack is horizontally placed between the positioning top block and the first rotating pad, which is connected to the x-axis angular displacement main component, allowing relative rotation during movement. The second piezoelectric ceramic stack is also horizontally placed between the positioning top block and the second rotating pad, which is connected to the x-axis angular displacement main component, allowing relative rotation during movement.

[0007] Preferably, the dimensions of each component are optimized through simulation to determine the key dimensions that affect the displacement amplification ratio of the piezoelectric ceramic stack, thereby enabling the platform to have a larger rotational stroke and better overall performance.

[0008] Preferably, the x-axis angular displacement main component and the y-axis angular displacement main component each consist of two L-shaped connecting rods, three rotating blocks, and three support blocks. Two of the support blocks are connected by opposite-direction flexible hinges, and the other support block is connected to the base by an opposite-direction hinge. The opposite-direction hinges give both the x-axis and y-axis angular displacement main components two degrees of rotational freedom. That is, the x-axis angular displacement main component can rotate around the y-axis while simultaneously achieving decoupled rotation around the x-axis via the opposite-direction hinges; similarly, the y-axis angular displacement main component can rotate around the x-axis while simultaneously achieving decoupled rotation around the y-axis. The two angular displacement main components are arranged in a cross shape, with a single rotating block connecting the two axes in the middle. The L-shaped connecting rods and support blocks are connected by rotating blocks, and the midpoints of the four sides of the angular displacement positioning platform are connected to the L-shaped connecting rods by flexible hinges. Leverage can be used to amplify the output displacement with a rotational effect, increasing the displacement amplification ratio while achieving large-stroke deflection.

[0009] Preferably, the x-axis angular displacement main component and the y-axis angular displacement main component are integrally machined by wire cutting, and all components are connected by flexible hinges to ensure the continuity of motion and reduce unnecessary errors in key components due to assembly.

[0010] Preferably, the first and second rotating pads and the support blocks on the x and y axis angular displacement main components are connected by flexible hinges to ensure that the output force of the piezoelectric ceramic stack is transmitted horizontally to the support blocks through the first and second rotating pads. When the support blocks rotate and amplify the force, the piezoelectric ceramic stack is prevented from being subjected to bending moment force, which would damage the piezoelectric ceramic stack and affect its service life.

[0011] Preferably, a groove is provided on the contact surface of the positioning top block with the first piezoelectric ceramic stack and the second piezoelectric ceramic stack. The groove can support and position the piezoelectric ceramic stack.

[0012] Two degrees of freedom of rotation represent an improvement on one degree of rotation. Due to the presence of oppositely oriented flexible hinges in the structure, it possesses rotational degrees of freedom in two directions, and these two rotational degrees of freedom are decoupled. Controlling the input voltages of the two piezoelectric ceramic stacks causes the rotation axis of the angular displacement positioning platform to move in the first quadrant of the xoy plane. When the input voltage signals of the two piezoelectric ceramic stacks are the same, the rotation axis rotates 45 degrees counterclockwise along the x-axis or 45 degrees clockwise along the y-axis.

[0013] The platform is driven by two piezoelectric ceramic stacks in (θ) x -θ y The angular displacement of the device is reduced by 100° compared to the rotational freedom of two degrees of rotation achieved by four piezoelectric ceramic stacks, saving on actuator and manufacturing costs. Furthermore, the invention is compact, compressible, miniaturized, and lightweight, and can be applied in fields such as optical communication, aerospace remote sensing, semiconductors, and biomedicine. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the overall structure of the present invention, with the upper left corner of the diagram representing the coordinate system. Detailed Implementation

[0015] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0016] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present invention are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indication will also change accordingly.

[0017] Furthermore, in this invention, descriptions involving "first," "second," etc., are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature; secondly, in the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0018] In this invention, unless otherwise explicitly specified and limited, the terms "connection" and "fixed" should be interpreted broadly. For example, "fixed" can mean a fixed connection, a detachable connection, or an integral part; it can mean a mechanical connection or an electrical connection; it can mean a direct connection or an indirect connection through an intermediate medium; it can mean the internal connection of two elements or the interaction between two elements. Unless otherwise explicitly limited, those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0019] Furthermore, the technical solutions of the various embodiments of the present invention can be combined with each other, but only if they are feasible for those skilled in the art. If the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the scope of protection claimed by the present invention.

[0020] Please see Figure 1 , Figure 1 This is a schematic diagram of the overall structure of the present invention, with the upper left corner of the diagram representing the coordinate system.

[0021] An embodiment of the present invention provides a two-degree-of-freedom angular displacement piezoelectric actuation platform. The component names corresponding to the numbers in the figure are as follows: angular displacement positioning platform 1, x-axis angular displacement main component 2, y-axis angular displacement main component 3, preload bolt 4, positioning top block 5, first piezoelectric ceramic stack 6, first rotating pad 7, support block 8, rotating block 9, flexible hinge 10.

[0022] The x-axis angular displacement main component 2 and the y-axis angular displacement main component 3 are cross-connected along the x-axis and y-axis, respectively. An angular displacement positioning platform 1 is positioned above the x-axis and y-axis angular displacement main components 2 and 3. Two pre-tightening bolts 4 are screwed into the x-axis and y-axis angular displacement main components 2 and 3, with the bottom ends of the two pre-tightening bolts 4 resting on adjacent surfaces of the positioning top block 5. A piezoelectric ceramic stack is horizontally placed between the positioning top block 5 and the first rotating pad 7. A rotating block 9 connects the x-axis and y-axis angular displacement main components 2 and 3. Two L-shaped connecting rods on each axis support the rotating platform. The two rotating blocks 9 at both ends are connected to the support blocks 8, forming a closed-loop structure that amplifies the displacement of the piezoelectric ceramic stack. The piezoelectric ceramic stack cannot be subjected to bending moment and shear force. A flexible hinge 10 is used to transition between the rotating pad and the support block, horizontally outputting the thrust of the piezoelectric ceramic stack, protecting the actuator, and also contributing to the displacement amplification of the piezoelectric ceramic stack. Both the support block and the L-shaped rod amplify the output displacement of the piezoelectric ceramic stack twice, effectively increasing the rotation stroke of the rotating platform.

[0023] The two-degree-of-freedom angular displacement piezoelectric actuator platform employs wire cutting technology, ensuring dimensional accuracy of the platform's intricate structures and the overall structural integrity. Flexible hinges connect all components, resulting in high structural rigidity, continuous motion, and high positioning accuracy, while minimizing errors caused by assembly issues in critical components. Grooves on the positioning top block allow piezoelectric ceramics to be stacked and embedded within them, providing support and positioning.

[0024] The use and working method of this invention are as follows:

[0025] When the platform rotates around the y-axis in one degree of freedom, a voltage is applied to the first piezoelectric ceramic stack 6 on the x-axis. The output displacement pushes the first rotating pad 7 to move to the right. The support block 8 of the x-axis angular displacement main component 2 is subjected to force and rotates around the bottom flexible hinge 10. According to the lever amplification principle, the output displacement of the first piezoelectric ceramic stack 6 is amplified by the support block 8 of the x-axis angular displacement main component 2 and acts on the rotating block 9 of the x-axis angular displacement main component 2. Since the flexible hinge connection points of the rotating block are not on a straight line but are distributed in a V-shape, the rotation of the rotating block 9 of the x-axis angular displacement main component 2 causes the two L-shaped connecting rods on the x-axis to rotate clockwise. One pushes upward and the other pulls downward, which together form the rotational effect of the platform. After displacement amplification by the L-shaped connecting rods, the rotational stroke of the platform is further increased.

[0026] The platform has two degrees of freedom of rotation. The first and second piezoelectric ceramic stacks are simultaneously energized, forming a composite rotational system. Because each support block 8 is separated by opposing hinges, the platform can rotate around the x and y axes respectively, and the two rotational degrees of freedom are decoupled. Influenced by the two input voltages, the platform's composite axis of rotation can move. To better describe the axis's position, a planar coordinate system xoy is defined on the rotating platform, with the angle between the axis and the x-axis denoted as A, ranging from 0 to 90 degrees. The axis moves through the origin o in the first and third quadrants. When the input voltage signals for both piezoelectric ceramic stacks are the same, the axis is at 45 degrees counterclockwise on the x-axis. When one piezoelectric ceramic stack is working, the axis is on either the x-axis or the y-axis.

[0027] Therefore, this invention provides a two-degree-of-freedom angular displacement piezoelectric actuation platform, which uses two piezoelectric ceramic stacks to drive two rotational degrees of freedom (θ). x -θ y The angular displacement positioning of this device, compared to achieving two degrees of freedom with four piezoelectric ceramic stacks, reduces the need for actuators, saving costs and reducing energy consumption. Furthermore, its compact structure, compressibility, miniaturization, and movable shaft increase the platform's applicability and adjustability, enabling applications in optical communication, aerospace remote sensing, semiconductors, biomedicine, and other fields, thus enhancing its application in various sectors.

[0028] The above are merely preferred embodiments of the present invention. It should be noted that the above preferred embodiments should not be considered as limitations on the present invention, and the scope of protection of the present invention should be determined by the scope defined in the claims. For those skilled in the art, several improvements and modifications can be made without departing from the spirit and scope 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 two-degree-of-freedom angular displacement piezoelectric actuated platform, characterized in that, The angle displacement positioning platform, the x-axis angle displacement main body component, the y-axis angle displacement main body component, the pre-tightening bolt, the positioning top block, the first piezoelectric ceramic stack, the second piezoelectric ceramic stack, the first rotating pad block, and the second rotating pad block are cross-connected along the x-axis and the y-axis, respectively; the angle displacement positioning platform is arranged above the x-axis angle displacement main body component and the y-axis angle displacement main body component; the pre-tightening bolt is screwed into the x-axis angle displacement main body component and the y-axis angle displacement main body component; the bottom end of the pre-tightening bolt is in abutment with the positioning top block; the first piezoelectric ceramic stack is horizontally arranged between the positioning top block and the first rotating pad block; the first rotating pad block is connected with the x-axis angle displacement main body component; the second piezoelectric ceramic stack is horizontally arranged between the positioning top block and the second rotating pad block; and the second rotating pad block is connected with the x-axis angle displacement main body component. The x-axis angle displacement main body component and the y-axis angle displacement main body component are composed of two L-shaped connecting rods, three rotating blocks, and three supporting blocks; two supporting blocks are connected by flexible hinges in different directions, and the other supporting block is connected with the base by a flexible hinge; the angle displacement main body components of the two axes are cross-connected, and a rotating block in the middle realizes the connection between the x-axis and the y-axis; the L-shaped connecting rods and the supporting blocks form two cross-connected closed loops through the rotating blocks and the base; and the connection points of the angle displacement positioning platform and the L-shaped connecting rods are at the middle points of the four edges of the platform.

2. The two-degree-of-freedom angular displacement piezoelectric actuated platform according to claim 1, wherein, The first rotating pad block and the supporting block on the x-axis angle displacement main body component are connected by a flexible hinge, and the second rotating pad block and the supporting block on the y-axis angle displacement main body component are connected by a flexible hinge.

3. The two-degree-of-freedom angular displacement piezoelectric actuated platform according to claim 1, wherein, Grooves are arranged on the contact surfaces of the positioning top block and the first piezoelectric ceramic stack and the second piezoelectric ceramic stack.

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