Lever displacement amplification three-axis fully decoupled tool servo device and method

Abstract

The present invention discloses a lever displacement amplifying three-axis fully decoupled tool servo device and method; the tool servo device includes a mounting base, a three-axis amplifying drive module, a three-axis decoupling module, a tool holder and a tool. The tool is fixed on the tool holder. The three-axis amplifying drive module includes three single-axis drive modules and three motion guide mechanisms. The motion displacement amplifying drive structure in the single-axis drive module includes a piezoelectric stack, a directional output structure and a trapezoidal lever. The present invention integrates a three-axis amplifying drive module with a symmetrical structure on two mutually perpendicular mounting plates, and realizes the three-dimensional spatial movement of the tool through piezoelectric drive, which has the advantages of large stroke, compact structure, high driving force, high resolution, high frequency response and high motion bandwidth. The present invention designs the lever of the motion displacement amplifying drive structure as a trapezoidal structure with a middle thickness greater than the thickness at both ends, which reduces the driving displacement error caused by the bending deformation of the lever while making the lever lighter.

Description

Technical Field

[0001] The present invention belongs to the technical field of ultra-precision metal cutting and processing, and in particular relates to a lever displacement amplification three-axis fully decoupled tool servo device and method. Background Art

[0002] Optical microstructured surfaces, such as diffraction elements, artificial compound eyes, and two-dimensional grating structures, possess numerous advantages for enhancing optical system performance, simplifying system architecture, and improving imaging quality. These properties offer highly attractive application prospects in optical imaging, photodetection, high-energy lasers, and other fields. Despite their numerous functional advantages, the high complexity and nanometer-precision features required of these surfaces pose significant challenges in their fabrication. Currently, the main fabrication technologies for optical microstructured surfaces include high-energy beam fabrication, photolithography, special energy field processing, ultra-precision machining using natural tools, and nanoimprinting for mass production. In contrast, ultra-precision cutting techniques (such as diamond turning and milling) leverage the exceptional characteristics of cutting tools to produce ultra-smooth, high-precision, complex surfaces. These techniques are considered highly promising and effective means for the ultra-precision creation of optical microstructured surfaces and are widely used in the fabrication of optical components such as microgratings, microdiffraction, and microlens arrays.

[0003] In the field of diamond ultra-precision machining, fast tool servo (FTS) systems have become a rapidly developing technology for creating optical microstructured surfaces in recent years due to their advantages, including high machining efficiency, wide material applicability, low cost, and high flexibility in creating complex structures. FTS technology achieves dynamic modulation at the micro- and nanoscale by driving the tool at high frequencies, enabling the machining trajectory to precisely match the geometric features of complex surfaces, thus overcoming the limitations of traditional ultra-precision turning. Currently, common FTS systems primarily utilize single-axis drive, using various drive methods, including piezoelectric stack drive, Lorentz electromagnetic force drive, and Maxwell electromagnetic force drive. Piezoelectric drive, due to its high force density and fast response, has been widely used in micro- and nano-precision machining. However, single-axis FTS structures are unable to meet the machining requirements of complex three-dimensional optical surfaces. Consequently, multi-axis tool servo technology has gradually become a research hotspot, with researchers both domestically and internationally dedicated to developing FTS systems with two, three, and even more degrees of freedom to enhance the machining capabilities of complex surfaces.

[0004] In existing multi-axis FTS systems, piezoelectric stack actuation remains the mainstream solution, often combined with a single-axis flexure hinge mechanism to achieve high-precision motion control. However, the limited strain capacity of piezoelectric materials results in a relatively small actuation stroke (typically a few to tens of microns), making it difficult to meet the demands of large-scale dynamic processing. To increase the piezoelectric actuation stroke, researchers have introduced multi-stage displacement amplification mechanisms using single-axis flexure hinges, such as bridge mechanisms, lever mechanisms, and Scott–Russell mechanisms, effectively improving the motion stroke. Summary of the Invention

[0005] The object of the present invention is to provide a lever displacement amplification three-axis fully decoupled tool servo device and method.

[0006] In a first aspect, the present invention provides a lever displacement amplification three-axis fully decoupled tool servo device, which includes a mounting base, a three-axis amplification drive module, a three-axis decoupling module, a tool holder and a tool.

[0007] The tool is fixed to the tool holder and pre-tightened with set screws to ensure it does not loosen or shift during machining. The three-axis decoupling module comprises three orthogonally arranged decoupling units. These units utilize a dual straight circular linkage mechanism connected between the tool holder and the mounting base. This connection effectively decouples the corresponding output terminals of the three axes, preventing interference between the motions of the individual axes.

[0008] The three-axis decoupling module is a key component in achieving precise control of the device. It comprises three orthogonally arranged decoupling units. Structurally, each of these units is connected to four parallel, dual straight-circular linkages. These linkages work together to provide the mechanical foundation for decoupling motion in three directions, ensuring independent and precise tool movement in different axes.

[0009] The three-axis amplification drive module includes three single-axis drive modules and three motion guide mechanisms. Each single-axis drive module includes one or two symmetrical motion displacement amplification drive structures; each motion guide mechanism is connected to each decoupling unit at one end and to the motion displacement amplification drive structure at the other end. The three single-axis drive modules, three motion guide mechanisms, and three decoupling units correspond to each other. Through their corresponding motion guide mechanisms and decoupling units, the three single-axis drive modules can precisely drive the tool holder in three different directions.

[0010] The motion displacement amplification drive structure includes a piezoelectric stack, a directional output structure, and a trapezoidal lever. The two ends of the piezoelectric stack respectively abut against the mounting base and the directional output structure. The two ends of the trapezoidal lever are respectively referred to as the fulcrum end and the amplification end. The fulcrum end of the trapezoidal lever is connected to the mounting base via a single-axis flexible hinge. The drive input position on the side of the trapezoidal lever is connected to the directional output structure via a single-axis flexible hinge. The thickness of the trapezoidal lever gradually decreases in the direction from the drive input position to the two ends. The amplification end of the trapezoidal lever is connected to the tool holder via a corresponding motion guide mechanism and a decoupling unit.

[0011] The motion-displacement amplification drive structure comprises three straight circular hinges, with the lever portion adopting a unique trapezoidal configuration. The drive input for the trapezoidal lever is located at the trisection point near the fulcrum end of the lever. This design leverages the principle of leverage to amplify the minute displacements generated by the piezoelectric stack, thereby meeting the larger tool travels required during machining.

[0012] At the same time, the parallel straight hinge mechanisms in the directional output structure are arranged in pairs, and the piezoelectric stacks are orthogonally distributed at the ends of the two parallel hinge mechanisms. They are pre-tightened by tail pre-tightening screws to ensure the stability and reliability of the piezoelectric stacks during operation.

[0013] Preferably, the motion guide mechanism includes a restraining structure and a connecting rod. The restraining structure includes multiple parallel guide blocks. One end of the guide block is connected to the mounting base via a uniaxial flexible hinge. The other end of the guide block is connected to the side of the connecting rod via a uniaxial flexible hinge. The axes of the connecting rods in the three motion guide mechanisms are perpendicular to each other.

[0014] Preferably, the decoupling unit utilizes a dual straight-circular linkage mechanism, specifically four parallel decoupling rods arranged in a matrix. One end of each of the four decoupling rods is connected to the end of a corresponding connecting rod in the motion guide mechanism via a multi-axis flexible hinge. The other ends of each of the four decoupling rods in the same decoupling unit are connected to the tool holder via a multi-axis flexible hinge.

[0015] Preferably, the three single-axis drive modules are an X-axis drive module, a Y-axis drive module, and a Z-axis drive module. The X-axis drive module and the Y-axis drive module each include only one motion displacement amplifying drive structure; the Z-axis drive module includes two symmetrically arranged motion displacement amplifying drive structures.

[0016] Preferably, the mounting base includes two mounting plates arranged perpendicular to each other. The X-axis drive module and the Y-axis drive module are symmetrically mounted on opposite sides of the two mounting plates. The two motion displacement amplification drive structures in the Z-axis drive module are symmetrically mounted on adjacent sides of the two mounting plates. The motion guide mechanism corresponding to the Y-axis drive module is provided with two constraint structures symmetrically mounted on adjacent sides of the two mounting plates.

[0017] Preferably, the mounting base further comprises a fixing seat; the fixing seat is in the shape of a triangular prism with a right triangle cross section; and the two mounting plates are respectively fixed on two mutually perpendicular side surfaces of the fixing seat.

[0018] Preferably, the side of the trapezoidal lever close to the directional output structure is a planar structure; and the side of the trapezoidal lever away from the directional output structure is provided with an inclined surface with a gradually changing thickness.

[0019] Preferably, the dual-parallel hinge mechanism employed in the directional output structure comprises an output block and two sets of elastic connecting plates. The two sets of elastic connecting plates are connected to opposite sides of the output block. Each set of elastic connecting plates comprises multiple elastic connecting plates arranged parallel to each other and spaced apart. One end of the elastic connecting plate is connected to the output block, and the other end is connected to the mounting base. The output block is connected to the side of the trapezoidal lever.

[0020] Preferably, the tool servo device further includes a three-axis displacement detection module. The three-axis displacement detection module includes a measuring block, a sensor mounting block, and three displacement sensors. The sensor mounting block is fixed to the mounting base. The measuring block is fixed to the tool holder. The three displacement sensors are orthogonally arranged on the sensor mounting block. The detection portions of the three displacement sensors are respectively oriented toward the measuring block.

[0021] In a second aspect, the present invention provides a tool servo method utilizing the aforementioned tool servo device. The tool servo method comprises the following steps: During tool machining of a workpiece, the piezoelectric stacks in one or more corresponding single-axis drive modules are controlled to perform telescopic motion according to the target movement direction of the tool, thereby maneuvering the tool in the target movement direction. A three-axis displacement detection module detects tool displacement; based on the measured displacement, negative feedback is applied to the input signals of the piezoelectric stacks of the single-axis drive modules until the tool reaches the target position.

[0022] The present invention has the following beneficial effects.

[0023] The present invention integrates a three-axis amplification drive module with a symmetrical structure on two mutually perpendicular mounting plates, and realizes the three-dimensional spatial movement of the tool through piezoelectric drive. It has the advantages of large stroke, compact structure, high driving force, high resolution, high frequency response, and high motion bandwidth.

[0024] The present invention designs the lever of the motion displacement amplification drive structure into a trapezoidal structure with a middle thickness greater than the thickness at both ends, and sets the thrust application point of the piezoelectric stack at the position of maximum thickness of the trapezoidal lever, thereby reducing the driving displacement error caused by the bending deformation of the lever while making the lever lighter.

[0025] The present invention uses four decoupling units based on a multi-axis flexible hinge structure arranged in a matrix to decouple the motion between the motion guide mechanism and the tool holder, thereby improving the displacement control accuracy of the tool holder in different directions and minimizing the influence of the preload force on the coupling disturbance. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a schematic diagram of the overall structure of the present invention.

[0027] Figure 2 It is a side structural schematic diagram of the present invention.

[0028] Figure 3 This is a schematic diagram of the positions of the three-axis amplification drive module, the three-axis decoupling module, the tool holder, and the tool on the two mounting plates in the present invention.

[0029] Figure 4 It is a structural schematic diagram of the fixing seat in the present invention.

[0030] Figure 5 This is a simulation diagram of the maximum displacement deformation of the tool servo device provided by the present invention along the z-axis direction.

[0031] Figure 6 This is a simulation diagram of the maximum displacement deformation of the tool servo device provided by the present invention along the y-axis direction.

[0032] Figure 7 This is a frequency simulation diagram of the tool servo device provided by the present invention along the z-axis direction.

[0033] Figure 8 This is a frequency simulation diagram of the tool servo device provided by the present invention along the x-axis direction.

[0034] Figure 9 This is a frequency simulation diagram of the tool servo device provided by the present invention along the y-axis direction.

[0035] Figure markings: 1. Mounting base; 1-1. Fixing seat; 1-2. Mounting plate; 2. Three-axis displacement detection module; 2-1. Measuring block; 2-2. Sensor mounting seat; 2-3. Displacement sensor; 3. Tool holder; 4. Tool; 5. Three-axis decoupling module; 6. Motion displacement amplification drive structure; 6-1. Piezoelectric stack; 6-2. Directional output structure; 6-3. Trapezoidal lever; 7. Motion guide mechanism; 7-1. Constraint structure; 7-2. Connecting rod; 8. X-axis drive module; 9. Y-axis drive module; 10. Z-axis drive module. DETAILED DESCRIPTION

[0036] The present invention will be further described below.

[0037] In order to more clearly present the purpose of the present invention, the technical solutions adopted, and the advantages thereof, the present invention will be explained in more detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only used to illustrate the present invention and do not limit the scope of protection of the present invention.

[0038] The uniaxial flexible hinge described in this embodiment refers to a flexible hinge that allows rotation in only a single direction, such as a unidirectional semicircular notch flexible hinge, a cross-spring flexible hinge, or other flexible hinge structures that meet the motion requirements. The multi-axis flexible hinge described in this embodiment refers to a flexible hinge that allows rotation in two or more directions, such as a bidirectional semicircular notch flexible hinge, an omnidirectional notch flexible hinge, or other flexible hinge structures that meet the motion requirements, preferably a flexible hinge with a double straight circle structure.

[0039] like Figure 1 and Figure 2 As shown, a lever displacement amplifying three-axis fully decoupled tool servo device includes a mounting base 1, a three-axis amplifying drive module, a three-axis decoupling module 5, a tool holder 3, a tool 4 and a three-axis displacement detection module 2. The mounting base 1 includes a fixed seat 1-1 and two mounting plates 1-2 arranged perpendicular to each other. The fixed seat 1-1 is in the shape of a triangular prism and has two mutually perpendicular sides. The two mounting plates 1-2 are respectively fixed on the two mutually perpendicular sides by bolts. The tool holder 3 and the mounting base 1 are movably connected through the three-axis amplifying drive module and the three-axis decoupling module 5. The tool 4 is fixed on the tool holder 3. The three-axis amplifying drive module is used to drive the tool holder 3 to move in three degrees of freedom. In this embodiment, the tool 4 is a diamond tool.

[0040] like Figure 1 and Figure 3As shown, the three-axis amplification drive module includes four motion displacement amplification drive structures 6 and three motion guide mechanisms 7. The first motion displacement amplification drive structure 6 serves as the X-axis drive module 8; the second motion displacement amplification drive structure 6 serves as the Y-axis drive module 9; and the third and fourth motion displacement amplification drive structures 6 together constitute the Z-axis drive module 10. The X-axis drive module 8, the Y-axis drive module 9, and the Z-axis drive module 10 are respectively connected to the three mutually orthogonal sides of the tool holder 3 via the three motion guide mechanisms 7 and the three-axis decoupling module 5, thereby achieving three-degree-of-freedom drive of the tool holder 3. The installation position and posture of each motion displacement amplification drive structure 6 are set according to the displacement direction of the drive. The two motion displacement amplification drive structures 6 corresponding to the X-axis drive module 8 and the Y-axis drive module 9 are respectively installed on opposite sides of the two mounting plates 1-2. The two motion displacement amplification drive structures 6 corresponding to the Z-axis drive module 10 are installed on adjacent sides of the two mounting plates 1-2, thereby forming a symmetrical drive structure.

[0041] The three motion guide mechanisms 7 correspond to the X-axis drive module 8, the Y-axis drive module 9, and the Z-axis drive module 10, respectively. The motion guide mechanism 7 includes a constraint structure 7-1 and a connecting rod 7-2. The constraint structure 7-1 includes two guide blocks. The two guide blocks are parallel to each other; one end of the two guide blocks is connected to the mounting base 1 through a single-axis flexible hinge. The other ends of the two guide blocks are connected to the side of the connecting rod 7-2 through a single-axis flexible hinge. The two guide blocks form a parallelogram flexible structure, so that the connecting rod 7-2 can only move linearly. The axes of the connecting rods 7-2 in the three motion guide mechanisms 7 are perpendicular to each other.

[0042] Each motion guide mechanism 7 may be provided with one or more constraint structures 7-1. In this embodiment, the motion guide mechanisms 7 corresponding to the X-axis drive module 8 and the Y-axis drive module 9 are provided with only one constraint structure 7-1; the motion guide mechanism 7 corresponding to the Z-axis drive module 10 is provided with two symmetrical constraint structures 7-1.

[0043] In this embodiment, the support and flexible deformation of the constraint structure 7-1 allow the connecting rod 7-2 to move smoothly during the displacement feeding process without deflection, thereby ensuring the accuracy of the tool displacement.

[0044] The motion displacement amplification drive structure 6 comprises a piezoelectric stack 6-1, a directional output structure 6-2, and a trapezoidal lever 6-3. The directional output structure 6-2 comprises an output block and two sets of elastic connectors. The two sets of elastic connectors are connected to opposite sides of the output block. Each set of elastic connectors includes two parallel, spaced-apart elastic connectors. One end of the elastic connector is connected to the output block, and the other end is connected to the mounting base 1.

[0045] Piezoelectric stack 6-1 is mounted in a corresponding groove structure on mounting base 1. Its two ends rest against mounting base 1 and the output block, respectively. Two sets of elastic connectors constrain the output block's movement, limiting it to a direction parallel to the axis of piezoelectric stack 6-1 and protecting it from shear forces.

[0046] The two ends of the trapezoidal lever 6-3 are respectively called the fulcrum end and the amplified end. The fulcrum end of the trapezoidal lever 6-3 is connected to the mounting base 1 via a uniaxial flexible hinge, while the amplified end of the trapezoidal lever 6-3 is connected to the corresponding connecting rod 7-2 via a uniaxial flexible hinge. The side of the trapezoidal lever 6-3 is connected to the side of the output block facing away from the piezoelectric stack 6-1 via a uniaxial flexible hinge. The side of the trapezoidal lever 6-3 closest to the piezoelectric stack 6-1 is flat, while the side facing away from the piezoelectric stack 6-1 is a trapezoidal surface.

[0047] The trapezoidal structure makes the trapezoidal lever 6-3 present a structure in which the thickness in the middle is greater than the thickness at both ends. The position where the output block is connected on the trapezoidal lever 6-3 is aligned with the position where the thickness of the trapezoidal lever 6-3 is the largest.

[0048] When the trapezoidal lever 6-3 is subjected to the thrust provided by the piezoelectric stack 6-1 and rotates and displaces around the fulcrum, it drives the connecting rod 7-2 to displace; during this process, the trapezoidal lever 6-3 will be subjected to bending moment; at this time, the trapezoidal lever 6-3 will undergo a certain degree of bending deformation, thereby affecting the output displacement accuracy of the three-axis amplification drive module; in this embodiment, the lever is designed as a trapezoidal structure, and the position of the driving force is arranged at the maximum thickness of the trapezoidal lever 6-3, which helps to minimize the bending deformation of the lever during the driving process.

[0049] In the motion displacement amplification drive structure 6, when voltage is applied to the piezoelectric stack, due to the inverse piezoelectric effect, an axial force is generated at the front and rear output ends of the piezoelectric stack, thereby pushing the trapezoidal lever 6-3 to amplify the displacement and transmitting the displacement through the connecting rod 7-2.

[0050] In this embodiment, the piezoelectric stack 6 - 1 in the X-axis driving module 8 and the Y-axis driving module 9 is arranged horizontally; and the piezoelectric stack 6 - 1 in the Z-axis driving module 10 is arranged vertically.

[0051] The three-axis decoupling module 5 comprises three orthogonally arranged decoupling units. Each of the three decoupling units corresponds to one of the three motion guide mechanisms 7. Each decoupling unit comprises four parallel decoupling rods arranged in a matrix. One end of each of the four decoupling rods in the same decoupling unit is connected to the end of the connecting rod 7-2 in the corresponding motion guide mechanism 7 via a multi-axis flexible hinge. The other end of each of the four decoupling rods in the same decoupling unit is connected to the corresponding side surface of the tool holder 3 via a multi-axis flexible hinge.

[0052] In this embodiment, the three-axis decoupling module 5 is used to decouple motion between three axes. This mechanism is based on the precise control and isolation of motion in three mutually perpendicular directions (typically the X, Y, and Z axes). When the tool holder 3 moves along one axis, the three-axis decoupling module 5 effectively prevents interference or impact on the motion of the other two axes. This structure significantly improves the system's motion accuracy and stability.

[0053] The three-axis displacement detection module 2 includes a measuring block 2-1, a sensor mounting block, and three displacement sensors 2-3. The sensor mounting block is fixed to the mounting base. The measuring block 2-1 is fixed to the tool holder 3. The three displacement sensors 2-3 are arranged orthogonally to each other and are all fixed to the sensor mounting block. The detection parts of the three displacement sensors 2-3 are respectively oriented towards three orthogonal side surfaces on the measuring block 2-1. The three displacement sensors 2-3 can detect the three-axis displacement of the measuring block 2-1, thereby realizing negative feedback control of the three-axis displacement of the tool 4.

[0054] In this embodiment, the three-axis displacement detection module 2 can detect the displacement direction of the tool holder 3 to realize the servo process of the entire system movement.

[0055] In some preferred embodiments, the tool is fixed to the tool holder by a pre-tightening screw.

[0056] In some preferred embodiments, the tool holder and the measuring baffle 2 - 1 are fixed together by means of pre-tightening screws and fixing screws.

[0057] The working principle of the present invention is as follows:

[0058] When the tool needs to be moved along the x-axis, X-axis drive module 8 is activated. Voltage changes cause the piezoelectric stack within X-axis drive module 8 to generate an axial propulsion force, thereby driving the corresponding trapezoidal lever 6-3. This amplified displacement is transmitted through the corresponding constraint structure 7-1, thereby achieving X-axis movement of tool 4.

[0059] Similarly, when it is necessary to control the tool to move along the y-axis or z-axis, the Y-axis drive module 9 or the Z-axis drive module is started, and the corresponding piezoelectric stack generates a propulsion force in the axial direction through voltage changes, thereby driving the corresponding trapezoidal lever to move, thereby realizing the movement of the tool 4 in the y-axis or z-axis direction.

[0060] The tool servo device provided in this embodiment amplifies displacement through a lever and can completely decouple three axes. It has the advantages of high frequency response, sub-nanometer motion resolution, high driving force, and high motion bandwidth of piezoelectric stack drive, thereby achieving efficient cutting capabilities in single-point diamond turning.

[0061] In the Static Structural module of ANSYS software, the directional deformation simulation along the z-axis and y-axis is performed on the tool servo device provided in this embodiment. The results are as follows: Figure 5 and 6 As shown. Figure 5 and 6 It can be seen that when a force of 100N is applied to the two piezoelectric stack input ends of the z-axis, the tool servo device provided in this embodiment can achieve a maximum displacement of 33.879μm in the z-axis direction; when a force of 100N is applied to the input end of the y-axis piezoelectric stack, the maximum displacement in the y-axis direction can reach 27.886μm, which has a large stroke displacement and can meet the needs of large-stroke processing of complex optical microstructure surfaces.

[0062] In the Modal (modal analysis) module of ANSYS software, the total deformation (total deformation) simulation of the tool servo device provided in this embodiment is performed to display the frequency analysis results of the x, y, and z axes under the total deformation (total deformation). The results are as follows: Figure 7 、 8 , 9. From Figure 7 、 8 As can be seen from Figures 9, the tool servo device provided in this embodiment has a first-order frequency of 892.39 Hz on the z-axis, 1039.1 Hz on the x-axis, and 1042.7 Hz on the y-axis, which has high motion resolution and motion bandwidth and can meet the processing needs of complex optical surfaces.

[0063] The lever-displacement-amplified three-axis fully decoupled tool servo device provided in this embodiment breaks through the limitations of traditional FTS systems. By combining piezoelectric drive with a lever-amplification mechanism, it possesses superior performance advantages to meet the high-precision and long-stroke machining requirements in practical applications. The present invention achieves three-dimensional motion of the tool through piezoelectric drive and is capable of decoupling the three axes. It has the advantages of a large stroke, a compact structure, high driving force, suppression of motion coupling effects, high resolution, high-frequency response, and a high motion bandwidth. Its four double-straight-circular hinge decoupling devices in three directions around the tool holder minimize the effects of preload on coupling disturbances. The present invention has an optimized overall architecture, a compact size, convenient installation and integration, a reasonable, stable, and reliable structure, a large planar motion stroke, a wide bandwidth, and high motion precision, providing an innovative and practical solution for related fields.

[0064] The basic principles, main features, and advantages of the present invention are shown and described above. Those skilled in the art should understand that the present invention is not limited to the foregoing embodiments. The foregoing embodiments and descriptions are merely illustrative of the principles of the present invention. Various changes and modifications may be made to the present invention without departing from the spirit and scope of the present invention. Such changes and modifications are intended to fall within the scope of the present invention. The scope of protection claimed in the present invention is defined by the appended claims and their equivalents.

Claims

1. A lever displacement amplification three-axis fully decoupled tool servo device, comprising a mounting base (1), a three-axis amplification drive module, a three-axis decoupling module (5), a tool holder (3) and a tool (4); the tool (4) is fixed on the tool holder (3); and is characterized in that: The three-axis amplification drive module includes three single-axis drive modules and three motion guide mechanisms (7); each single-axis drive module includes one or more motion displacement amplification drive structures (6); the three-axis decoupling module (5) includes three decoupling units arranged orthogonally; the three single-axis drive modules, the three motion guide mechanisms (7), and the three decoupling units correspond to each other one by one; the three single-axis drive modules respectively drive the tool holder (3) to move in three different directions through the corresponding motion guide mechanisms (7) and decoupling units; The motion displacement amplification drive structure (6) comprises a piezoelectric stack (6-1), a directional output structure (6-2) and a trapezoidal lever (6-3); the two ends of the piezoelectric stack (6-1) respectively abut against the mounting base (1) and the directional output structure (6-2); the two ends of the trapezoidal lever (6-3) are respectively called a fulcrum end and an amplification end; the fulcrum end of the trapezoidal lever (6-3) is connected to the mounting base (1) through a single-axis flexible hinge; the driving input position on the side of the trapezoidal lever (6-3) is connected to the directional output structure (6-2) through a single-axis flexible hinge; the thickness of the trapezoidal lever (6-3) gradually decreases from the driving input position to the two ends; the amplification end of the trapezoidal lever (6-3) is connected to the tool holder (3) through a corresponding motion guide mechanism (7) and a decoupling unit.

2. The lever displacement amplification three-axis fully decoupled tool servo device according to claim 1, characterized in that: The motion guide mechanism (7) comprises a constraint structure (7-1) and a connecting rod (7-2); the constraint structure (7-1) comprises a plurality of guide blocks parallel to each other; one end of the guide block is connected to the mounting base (1) via a single-axis flexible hinge; the other end of the guide block is connected to the side of the connecting rod (7-2) via a single-axis flexible hinge; the axes of the connecting rods (7-2) in the three motion guide mechanisms (7) are perpendicular to each other.

3. The lever displacement amplification three-axis fully decoupled tool servo device according to claim 2, characterized in that: The decoupling unit comprises four mutually parallel decoupling rods arranged in a matrix; one end of each of the four decoupling rods is connected to the end of a connecting rod (7-2) in a corresponding motion guide mechanism (7) via a multi-axis flexible hinge; and the other ends of each of the four decoupling rods in the same decoupling unit are connected to a tool holder (3) via a multi-axis flexible hinge.

4. The lever displacement amplification three-axis fully decoupled tool servo device according to claim 2, characterized in that: The three single-axis drive modules are an X-axis drive module (8), a Y-axis drive module (9), and a Z-axis drive module (10); the X-axis drive module (8) and the Y-axis drive module (9) each include only one motion displacement amplifying drive structure (6); and the Z-axis drive module (10) includes two symmetrically arranged motion displacement amplifying drive structures (6).

5. The lever displacement amplification three-axis fully decoupled tool servo device according to claim 4, characterized in that: The mounting base (1) comprises two mounting plates (1-2) arranged perpendicular to each other; the X-axis drive module (8) and the Y-axis drive module (9) are symmetrically mounted on opposite sides of the two mounting plates (1-2); the two motion displacement amplification drive structures (6) in the Z-axis drive module (10) are symmetrically mounted on adjacent sides of the two mounting plates (1-2); and the motion guide mechanism (7) corresponding to the Y-axis drive module (9) is provided with two constraint structures (7-1) symmetrically mounted on adjacent sides of the two mounting plates (1-2).

6. The lever displacement amplification three-axis fully decoupled tool servo device according to claim 5, characterized in that: The mounting base (1) further comprises a fixing seat (1-1); the fixing seat (1-1) is in the shape of a triangular prism with a right-angled triangle cross section; and two mounting plates (1-2) are respectively fixed on two mutually perpendicular side surfaces of the fixing seat (1-1).

7. The lever displacement amplifying three-axis fully decoupled tool servo device according to claim 1, characterized in that: The side of the trapezoidal lever (6-3) close to the directional output structure (6-2) is a planar structure; the side of the trapezoidal lever (6-3) facing away from the directional output structure (6-2) is provided with an inclined surface with a gradually changing thickness; and the driving input position of the trapezoidal lever is located at a point of three equal divisions of the trapezoidal lever close to the fulcrum end.

8. The lever displacement amplifying three-axis fully decoupled tool servo device according to claim 1, characterized in that: The directional output structure (6-2) comprises an output block and two groups of elastic connecting pieces; the two groups of elastic connecting pieces are respectively connected to opposite sides of the output block; each group of elastic connecting pieces comprises a plurality of elastic connecting pieces that are parallel to each other and spaced apart; one end of the elastic connecting piece is connected to the output block, and the other end is connected to the mounting base (1); the output block is connected to the side of the trapezoidal lever (6-3).

9. The lever displacement amplifying three-axis fully decoupled tool servo device according to claim 1, characterized in that: The invention also includes a three-axis displacement detection module (2); the three-axis displacement detection module (2) includes a measuring block (2-1), a sensor mounting block and three displacement sensors (2-3); the sensor mounting block is fixed on the mounting base; the measuring block (2-1) is fixed on the tool holder (3); the three displacement sensors (2-3) are all orthogonally arranged on the sensor mounting block; and the detection parts of the three displacement sensors (2-3) are respectively oriented toward the measuring block (2-1).

10. A tool servo method, characterized in that: A lever displacement amplifying three-axis fully decoupled tool servo device as described in claim 9 is used; the tool servo method is as follows: during the process of tool machining a workpiece, according to the target moving direction of the tool, the piezoelectric stacks in the corresponding one or more single-axis drive modules are controlled to perform telescopic movement, so as to mobilize the tool to move in the target moving direction; the three-axis displacement detection module (2) detects the displacement of the tool; and the input signal of the piezoelectric stack of the single-axis drive module is negatively feedback-controlled according to the measured displacement until the tool reaches the target position.

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