Lever displacement amplification three-axis complete decoupling tool servo device and method

Abstract

The invention discloses a lever displacement amplification three-axis complete decoupling tool servo device and method. The tool servo device is provided with a base body, a three-axis amplification driving module, a three-axis decoupling module, a tool apron and a tool. And the cutter is fixed on the cutter holder. The three-axis amplification driving module comprises three single-axis driving modules and three motion guiding mechanisms. A motion displacement amplification driving structure in the single-axis driving module comprises a piezoelectric stack, a directional output structure and a trapezoidal lever. The three-axis amplification driving modules with symmetrical structures are integrated on the two mounting plates which are perpendicular to each other, three-dimensional space movement of the cutter is achieved through piezoelectric driving, and the three-axis amplification driving device has the advantages of being large in stroke, compact in structure, high in driving force, high in resolution ratio, high in frequency response and high in movement bandwidth. The lever of the motion displacement amplification driving structure is designed to be of a trapezoidal structure with the middle thickness larger than the thickness of the two ends, and the driving displacement error caused by bending deformation of the lever is reduced while the lever is lightened.

Description

Technical Field

[0001] The 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 microstructure surfaces, such as diffraction elements, artificial compound eyes, and two-dimensional grid structures, have many excellent characteristics in improving the performance of optical systems, simplifying system structures, and improving system imaging quality. These excellent characteristics show extremely attractive application prospects in the fields of optical imaging, photoelectric detection, and high-energy lasers. Although optical microstructure surfaces have many functional advantages, the high complexity of the surface structure and the requirements for nano-precision features pose more challenges to their processing and manufacturing processes. At present, the manufacturing technologies suitable for optical microstructure surfaces mainly include high-energy beam manufacturing technology, photolithography technology, special energy field processing technology, ultra-precision machining technology based on natural tools, and nano-imprinting technology for mass replication. In contrast, ultra-precision cutting technology (diamond turning, milling, etc.) has the advantage of being able to process ultra-smooth, high-precision complex surfaces with the help of excellent tool characteristics. It is considered to be a highly efficient means of ultra-precision creation of optical microstructure surfaces and is widely used in the manufacture of optical elements such as micro-gratings, micro-diffraction, and micro-lens arrays.

[0003] In the field of diamond ultra-precision machining technology, the Fast Tool Servo (FTS) system has become a rapidly developing technology for optical microstructure surface creation in recent years due to its advantages of high machining efficiency, wide range of material applications, low cost, and high flexibility in complex structure creation. FTS technology achieves micro-nano dynamic modulation through high-frequency driven tools, so that the machining trajectory can accurately match the geometric features of complex surfaces, thereby breaking through the machining limitations of traditional ultra-precision turning. At present, common FTS systems mainly use single-axis drive, and its driving methods include piezoelectric stack drive, Lorentz electromagnetic force drive, and Maxwell electromagnetic force drive. Among them, piezoelectric drive is widely used in the field of micro-nano precision machining due to its high force density and fast response. However, the single-axis driven FTS structure is difficult to meet the processing requirements of complex three-dimensional optical surfaces. Therefore, multi-axis tool servo technology has gradually become a research hotspot. Scholars at home and abroad have devoted themselves to developing dual-axis, three-axis, and even more degrees of freedom FTS systems to improve the processing capabilities of complex surfaces.

[0004] In the existing multi-axis FTS system, piezoelectric stack drive is still the mainstream solution, and it is combined with a single-axis flexible hinge mechanism to achieve high-precision motion control. However, the strain capacity of piezoelectric materials is limited, resulting in a small drive stroke (usually a few microns to tens of microns), which is difficult to meet the needs of large-scale dynamic processing. In order to increase the stroke of piezoelectric drive, researchers introduced multi-stage displacement amplification mechanisms of single-axis flexible hinges, such as bridge mechanisms, lever mechanisms, and Scott–Russell mechanisms, which effectively improved the motion stroke problem. Summary of the invention

[0005] The object of the present invention is to provide a lever displacement amplifying 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 on the tool holder and pre-tightened by fixing screws to ensure that the tool will not loosen or shift during processing. The three-axis decoupling module includes three decoupling units arranged orthogonally. The decoupling unit adopts a double straight circular connecting rod mechanism and is connected between the tool holder and the mounting base. This connection method can effectively realize the decoupling of the corresponding output ends of the three axes and avoid mutual interference between the movements of each axis.

[0008] The three-axis decoupling module is a key part to achieve precise control of the device, which includes three decoupling units arranged orthogonally. From the perspective of the device structure, each orthogonal arrangement is connected to four parallel double straight circular connecting rod mechanisms, which cooperate with each other to provide a mechanical basis for the decoupling of motion in three directions, ensuring that the tool can move independently and accurately in different axial directions.

[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; wherein one end of each motion guide mechanism is connected to each decoupling unit, and the other end is connected to the motion displacement amplification drive structure. The three single-axis drive modules, the three motion guide mechanisms, and the three decoupling units correspond one to one. The three single-axis drive modules can drive the tool holder to move precisely in three different directions through the corresponding motion guide mechanisms and decoupling units.

[0010] The motion displacement amplification driving 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 called the fulcrum end and the amplification end. The fulcrum end of the trapezoidal lever is connected to the mounting base through a uniaxial flexible hinge. The driving input position on the side of the trapezoidal lever is connected to the directional output structure through a uniaxial flexible hinge. The thickness of the trapezoidal lever gradually decreases in the direction from the driving input position of the trapezoidal lever to the two ends. The amplification end of the trapezoidal lever is connected to the tool holder through a corresponding motion guide mechanism and a decoupling unit.

[0011] The motion displacement amplification drive structure includes three straight circular hinges, in which the lever part adopts a unique trapezoidal configuration; the driving input position of the trapezoidal lever is designed at the trisection point of the trapezoidal lever close to the fulcrum end. This design can make full use of the lever principle to amplify the tiny displacement generated by the piezoelectric stack, thereby meeting the larger stroke required by the tool during the processing process.

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

[0013] Preferably, the motion guide mechanism comprises a constraint structure and a connecting rod. The constraint structure comprises a plurality of guide blocks parallel to each other. One end of the guide block is connected to the mounting base through a uniaxial flexible hinge. The other end of the guide block is connected to the side of the connecting rod through 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 adopts a double straight circular connecting rod mechanism, specifically four mutually parallel decoupling rods arranged in a matrix. One end of each of the four decoupling rods is connected to the end of the connecting rod in the corresponding motion guide mechanism through a multi-axis flexible hinge. The other ends of the four decoupling rods in the same decoupling unit are connected to the tool holder through 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 only include 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-angled 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 double parallel hinge mechanism used in the directional output structure specifically includes an output block and two groups of elastic connecting plates. The two groups of elastic connecting plates are respectively connected to opposite sides of the output block. Each group of elastic connecting plates includes a plurality of elastic connecting plates that are 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 comprises a three-axis displacement detection module. The three-axis displacement detection module comprises a measuring block, a sensor mounting block and three displacement sensors. The sensor mounting block is fixed on the mounting base. The measuring block is fixed on the tool holder. The three displacement sensors are all orthogonally arranged on the sensor mounting block. The detection parts of the three displacement sensors are respectively facing the measuring block.

[0021] In a second aspect, the present invention provides a tool servo method, which uses the aforementioned tool servo device; the tool servo method is as follows: in the process of machining a workpiece by the tool, according to the target moving direction of the tool, the corresponding piezoelectric stacks in 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 detects the displacement of the tool; according to the measured displacement, the input signal of the piezoelectric stack of the single-axis drive module is negatively feedback-controlled 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, realizes the three-dimensional spatial movement of the tool through piezoelectric drive, and 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 driving structure as 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, so that the displacement control accuracy of the tool holder in different directions is improved and the influence of the preload force on the coupling disturbance is minimized. 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 It 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 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 It 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 It 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 It is a frequency simulation diagram of the tool servo device provided by the present invention along the z-axis direction.

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

[0034] Fig. 9 It 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 is further described below.

[0037] In order to more clearly present the purpose of the present invention, the technical solutions adopted and the advantages possessed, the present invention will be explained in more detail below in combination with the accompanying drawings and specific embodiments. It should be clear that the specific embodiments described here are only used to explain 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 one 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 driving 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 is movably connected to the mounting base 1 through a three-axis amplifying driving module and a three-axis decoupling module 5. The tool 4 is fixed on the tool holder 3. The three-axis amplifying driving 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; 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 through the three motion guide mechanisms 7 and the three-axis decoupling module 5 to realize the 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 the 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 the 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 in a linear manner. The axes of the connecting rods 7-2 in the three motion guide mechanisms 7 are perpendicular to each other.

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

[0043] In this embodiment, the support and flexible deformation of the constraint structure 7-1 enable 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 driving structure 6 includes a piezoelectric stack 6-1, a directional output structure 6-2 and a trapezoidal lever 6-3. The directional output structure 6-2 includes an output block and two sets of elastic connecting plates. The two sets of elastic connecting plates are respectively connected to opposite sides of the output block. Each set of elastic connecting plates includes two elastic connecting plates that are 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 1.

[0045] The piezoelectric stack 6-1 is installed in the corresponding groove structure on the mounting base 1. The two ends of the piezoelectric stack 6-1 are respectively against the mounting base 1 and the output block. The two sets of elastic connecting pieces can constrain the moving direction of the output block, so that the output block can only move in the direction parallel to the axis of the piezoelectric stack 6-1, thereby preventing the piezoelectric stack 6-1 from being subjected to shear force.

[0046] The two ends of the trapezoidal lever 6-3 are respectively called the fulcrum end and the enlarged end. The fulcrum end of the trapezoidal lever 6-3 is connected to the mounting base 1 through a uniaxial flexible hinge, and the enlarged end of the trapezoidal lever 6-3 is connected to the corresponding connecting rod 7-2 through a uniaxial flexible hinge. The side of the trapezoidal lever 6-3 is connected to the side of the output block away from the piezoelectric stack 6-1 through a uniaxial flexible hinge. The side of the trapezoidal lever 6-3 close to the piezoelectric stack 6-1 is a flat surface, and the side 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 around the fulcrum, it drives the connecting rod 7-2 to move; 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 driving force is arranged at the place where the thickness of the trapezoidal lever 6-3 is the largest, which helps to minimize the bending deformation of the lever during the driving process.

[0049] In the motion displacement amplification driving structure 6, when a voltage is applied to the piezoelectric stack, an axial force is generated at the front and rear output ends of the piezoelectric stack due to the inverse piezoelectric effect, 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 includes three decoupling units arranged orthogonally. The three decoupling units correspond to three motion guide mechanisms 7 respectively. Each decoupling unit includes four mutually parallel decoupling rods arranged in a matrix. One end 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 through a multi-axis flexible hinge. The other ends of the four decoupling rods in the same decoupling unit are connected to the corresponding side surfaces on the tool holder 3 through a multi-axis flexible hinge.

[0052] In this embodiment, the three-axis decoupling module 5 is used for motion decoupling between the three axes. The principle of the three-axis motion decoupling mechanism is based on the precise control and isolation of motion in three mutually perpendicular directions (usually X, Y, and Z axes); when the tool holder 3 moves along one of the axes, the three-axis decoupling module 5 can effectively avoid interference or influence on the motion state of the other two axes. This structure can greatly improve the motion accuracy and stability of the system.

[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 on the mounting base. The measuring block 2-1 is fixed on the tool holder 3. The three displacement sensors 2-3 are arranged orthogonally to each other and are all fixed on the sensor mounting block. The detection parts of the three displacement sensors 2-3 are respectively facing the three orthogonal sides on the measuring block 2-1. The three-axis displacement of the measuring block 2-1 can be detected by the three displacement sensors 2-3, thereby realizing the 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: When the tool needs to be controlled to move along the x-axis, the x-axis drive module 8 is started, and the piezoelectric stack in the x-axis drive module 8 generates an axial propulsion force through voltage change, thereby driving the corresponding trapezoidal lever 6-3 to move. The amplified displacement is transmitted through the corresponding constraint structure 7-1, thereby realizing the movement of the tool 4 in the x-axis direction.

[0058] Similarly, when it is necessary to control the tool to move along the y-axis or z-axis direction, 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.

[0059] The tool servo device provided in this embodiment amplifies the displacement through a lever and can completely decouple the 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.

[0060] In the Static Structural module of the ANSYS software, the directional deformation simulation along the z-axis and y-axis directions of the tool servo device provided in this embodiment is performed. 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 maximum displacement of the tool servo device provided in this embodiment in the z-axis direction can reach 33.879μm; 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, with a large stroke displacement, which can meet the needs of large-stroke processing of complex optical microstructure surfaces.

[0061] In the Modal (modal analysis) module of the ANSYS software, the Total Deformation (total deformation) simulation is performed on the tool servo device provided in this embodiment, and the frequency analysis results of the x, y, and z axes under the Total Deformation (total deformation) are displayed. 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, and has a high motion resolution and motion bandwidth, which can meet the processing needs of complex optical surfaces.

[0062] The lever displacement amplification three-axis fully decoupled tool servo device provided in this embodiment breaks through the limitations of the traditional FTS system. By combining piezoelectric drive with a lever amplification mechanism, it has excellent performance advantages to meet the processing requirements for high precision and long stroke in practical applications. The present invention realizes the three-dimensional spatial movement of the tool through piezoelectric drive, and can decouple the three axes. It has the advantages of large stroke, compact structure, high driving force, suppression of motion coupling effect, high resolution, high frequency response, and high motion bandwidth. The four double straight circular hinge decoupling devices in three directions around the tool holder minimize the influence of preload force on coupling disturbance. The overall architecture of the present invention is optimized, compact, easy to install and integrate, reasonable, stable and reliable structure, large planar motion stroke, wide bandwidth, and high motion accuracy, providing innovative and practical solutions for related fields.

[0063] The above shows and describes the basic principles, main features and advantages of the present invention. It should be understood by those skilled in the art that the present invention is not limited to the above embodiments. The above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention to be protected. The scope of protection of the present invention is defined by the attached 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); characterized in that: The three-axis amplification drive module comprises three single-axis drive modules and three motion guide mechanisms (7); each single-axis drive module comprises one or more motion displacement amplification drive structures (6); the three-axis decoupling module (5) comprises 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 the decoupling units; The motion displacement amplifying driving 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 amplifying end; the fulcrum end of the trapezoidal lever (6-3) is connected to the mounting base (1) via 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) via a single-axis flexible hinge; the thickness of the trapezoidal lever (6-3) gradually decreases in the direction from the driving input position of the trapezoidal lever (6-3) to both ends; the amplifying end of the trapezoidal lever (6-3) is connected to the tool holder (3) via a corresponding motion guiding 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 which are 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; and 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 only include one motion displacement amplifying drive structure (6); and the Z-axis drive module (10) includes two motion displacement amplifying drive structures (6) that are symmetrically arranged.

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 amplification 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 trisection point of the trapezoidal lever close to the fulcrum end.

8. The lever displacement amplification 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 plates; the two groups of elastic connecting plates are respectively connected to opposite sides of the output block; each group of elastic connecting plates comprises a plurality of elastic connecting plates which are parallel to each other and arranged at intervals; one end of the elastic connecting plate 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 amplification three-axis fully decoupled tool servo device according to claim 1, characterized in that: It also comprises a three-axis displacement detection module (2); the three-axis displacement detection module (2) comprises a measuring block (2-1), a sensor mounting block and three displacement sensors (2-3); the sensor mounting block is fixed on a mounting base; the measuring block (2-1) is fixed on a 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 stack in the corresponding one or more single-axis drive modules is 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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